NC-2009 WEp1: Water Use Reduction—20% Reduction

  • NC CS Schools CI WEp1 Action Steps Diagram
  • The bar has been raised

    You will not earn this prerequisite using standard fixtures that only comply with the federal EPAct 1992. This prerequisite, first introduced in LEED 2009, raises the bar significantly. All projects must now reduce water use by at least 20% as a prerequisite, whereas earlier versions of LEED awarded a point for a 20% reduction. The baseline against which water savings are measured has also become more demanding. The LEED 2009 baseline for commercial lavatory faucets is 0.5 gallons per minute (gpm), whereas the previous baseline was 2.5 gpm. Note that this prerequisite addresses interior water use only, but can be coupled with other water credits addressing outdoor water use.

    Plan on focusing on efficiency with ultra-low-flow or waterless fixtures, as well as overall conservation with strategies like rainwater capture and graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. reuse (these strategies are documented as an alternative compliance path in LEED Online). Careful attention to fixture selection and flow rates can help projects achieve 20% or greater interior water savings  at minimal cost and without compromising comfort.

    Follow these key steps

    1. Determine Full Time Equivalent (FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories.) occupancy and Fixture Usage Groups.
    2. Determine the Baseline Case Water Use Budget for Indoor Water Use.
    3. Choose fixtures and water reduction or reuse strategies. 
    4. Estimate the project’s water usage by creating a Design Case Water Use Budget. 
    5. Use the LEED Online credit form to compare the baseline and design case water budgets to determine the water reduction percentage for the project. 
    6. Complete the LEED Online credit form and upload water fixture cut sheets.

    Sample water use reduction chart for a commercial building.

    In the example illustrated in this bar chart, 21% savings is achieved by looking for savings in the fixtures that use the most volume of water: toilets, urinals, and showers. This example assumes 1.28 gpf toilets, 0.5 gpf urinals, and 2.0 gpm showers. Sinks are a less likely target because baseline use is already very low in many cases.

    Only some water uses are under the LEED scope

    Project teams often assume that if a water fixture or process on their project uses water, then it must fall under the scope of this credit. However, only specific "regulated" fixtures fall under the scope. The following uses, among others, are not within the credit scope. Following efficient practices is a great idea for these uses, but it's simply not covered under the scope here.

    • "Process" water
    • Pot- or bucket-filling sinks
    • Bidets
    • Laboratory sinks
    • Dishwashers and other appliances

    Key guidance from USGBC

    Since LEED 2009 was launched, USGBC has developed and updated a key guidance document for WEp1 calculations: Water Use Reduction Additional Guidance. It provides indispensable guidance for fixture groups, total daily uses calculation, dual flush toilet flow rates, public metering faucet flow rate conversion, non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. use alternative compliance path and gender ratio guidance.

    For example, this document provides key guidance on when a non-default male-female gender ratio is appropriate—essentially, modifications to the 50:50 ratio must be shown to apply for the life of the building, with specific exceptions allowed.

  • A question of scope

    As of an addenda issued in May 2011, USGBC has clarified the scope of this prerequisite for addition projects. For additions to existing buildings, only the fixtures within the project scope must be counted for WEp1. To earn points under WEc3, all fixtures necessary to meet the needs of occupants using the addition must be included, including those located within the preexisting building.

  • FAQs for Water Use Reduction

    Will the reviewers accept a spreadsheet as a plumbing fixture schedule in lieu of the plans from the Construction Documents?

    A copy of the plumbing fixture schedule from the project's construction documents, outlining detailed information for each flush and flow fixture specified (including fixture manufacturer, model number and flow rate) helps the review team verify that those fixtures are part of the construction contract. In the absence of such documentation, a copy of project-specific specifications and details or a project-specific contractor’s submittal with manufacturer’s cut sheets highlighting flush and flow rates for each fixture specified can be provided.

    In LEED review comments I've been referred to the Water Use Reduction Additional Guidance document. I didn't know this was a required reference document.

    USGBC originally created this guidance document to address common questions project teams encountered when documenting WE credits. The calculations in these forms are fairly complex and are generally not addressed in the reference guide. The guidance document is intended to guide the user through the process of filling out the form, but is not intended to create any new requirements.

    Should I include bar sinks? What about mop sinks or janitor sinks? Swimming pools? Safety showers? Bidets? Tub spouts?

    If the bar sinks installed have a similar usage pattern and are similar fixture type as for those in kitchens then these should be included.

    Mop sinks, janitor sinks, swimming pools, bidets, and safety showers are considered process waterProcess water is used for industrial processes and building systems such as cooling towers, boilers, and chillers. It can also refer to water used in operational processes, such as dishwashing, clothes washing, and ice making. and are not included. Consider only the showerhead and not the tub spout.

    Additionally, commercial kitchen sinks and bar sinks including pot sinks, prep sinks, wash down, and cleaning sinks are considered process water and are not included.

    However, pre-rise spay valves must be considered. If your project is registered after the 11/1/2011 addenda release then the pre-rinse spray valve flow rate must be 1.6 gpm or less in order to comply with the prerequisite. If your project has a pre-rinse spray valve that has a higher flow rate than 1.6 gpm, then the project is not in compliance and the pre-rinse spray valve would need to be revised in order to be eligible for LEED certification.

    We provided showers to comply with the alternative transportation credit. Should they be considered in WEp1 calculations?

    Yes. Once you enter the project occupancy the WEp1 form calculates the default daily FTE shower uses.

    If those fixtures are outside the LEED Project Boundary, they should only be included if your project is LEED-CI, however.

    Can you explain the 12-second duration for metering faucets?

    This duration is intended to prevent LEED projects from claiming credit for reducing the duration below 12 seconds; durations less than 12 seconds are not permitted for LEED calculations as shorter intervals are insufficient for typical hand washing

    Can I use a nonpotable water source to contribute to WEp1 compliance?

    Yes. Although the focus is water efficiency of the installed fixtures, onsite sources of nonpotable water such as captured rainwater, graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area., air conditioner condensate, cooling tower bleed off water, etc., can be applied via an alternative compliance path. Refer to the Water Use Reduction Additional Guidance document for further information.

    Our project does not have any eligible water fixtures in the project boundary. Can we comply with WEp1?

    Yes, per LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10214: "A project without eligible water fixtures in the LEED-NC project boundary is exempt from WEp1. Should such a project wish to pursue points under WE Credit 3, they may do so by evaluating WEc3 performance based upon all of the fixtures that are necessary to meet the needs of the project occupants, even if they are located outside the project boundary."

    We are having trouble finding EPAct-compliant fixtures. Is that a problem?

    Not for individual fixtures. You only have to meet the LEED requirements for your fixtures as a group.

    Where can I find a clear meaning of "public" and "private" as relevant to lavatory faucets?

    Private usePrivate use applies to plumbing fixtures in residences, apartments, and dormitories, to private (non-public) bathrooms in transient lodging facilities (hotels and motels), and to private bathrooms in hospitals and nursing facilities. applies to plumbing fixtures in residences, apartments, and dormitories, to private (non-public) bathrooms in transient lodgingLodging are facilities that provide overnight accommodations to customers or guests, including hotels, motels, inns and resorts. facilities (hotels and motels), and to private bathrooms in hospitals and nursing facilities. Any fixtures that are not in one of those more residential-focused situations are considered to be public fixtures.

    Our project is a factory with historically a 95% male workforce. The restroom design accounts for this. Can I argue that the male/female gender ratio is different than 50/50?

    LEEDuser has seen numerous comments on our forums suggesting that reviewers are providing little leeway for situations like this, even in a case just like you describe. Even a 10% bump toward women to account for possible future trends was not deemed sufficient. At this point (February 2013), LEEDuser is not aware of clear guidance on when a nonstandard gender ratio would be accepted, nor are there any applicable LEED Interpretations for LEED 2009 projects. If you have any relevant experience on this, please let us know!

    Are shower duration controls an acceptable water-saving strategy?

    LEED assumes a baseline of 300 seconds for a shower, and LEEDuser has heard of review comments rejecting controls that would shorten this duration for the design case. A CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide or LEED Interpretation would likely be needed to make a case.

    Can I include process water savings in order to earn an Exemplary Performance point?

    Yes—refer to LEED Interpretation #5819, issued 8/31/2004 and modified 4/1/13 to apply to NC-v2.2 and NC-v2009 projects. Quoting the relevant text from LI #5819: “A whole building approach to process water must be used (including washing machines, dish washers, drinking fountains, cooling towers, etc.) The project must demonstrate a process water savings that is equal to or greater than 10% of the regulated water usage as calculated in WEc3. The project should obtain information on the average amount of water use for each type of equipment to determine an appropriate baseline and demonstrate that the increased efficiency compared to the baseline exceeds the 10% WEc3 threshold. Required submittals for this innovation would include: 1) A narrative explaining what strategies were used and how the baseline was developed. 2) Calculations demonstrating performance compared to the baseline. 3) Cut sheets showing water usage of equipment used.”

    NC projects have also had success using Schools WEc4 as an ID credit. Also see LEED Interpretations #808 (issued 7/8/2004) and #5752 (issued 5/13/2005) for some history on this issue. You can also earn an EP point for 45% savings under the Water Use Reduction credit, but it appears, based on the most recent ruling, that the 45% savings should be based on regulated (non-process) fixtures alone.

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Pre-Design

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  • Check local codes and incentives for water-saving opportunities and restrictions. Rebates are common, as are plumbing codes restricting some water-savings technologies such as waterless urinals, graywater reuse, on-site wastewater treatment and reuse, rainwater harvesting, composting toilets, and other strategies.


  • Graywater and rainwater collection systems may offer the potential for non-potable water to be used in interior applications, helping to achieve this prerequisite, and the additional water-reduction credit.


  • Perform a Water Balance Study for the entire project to make informed decisions about where to focus water savings efforts. Look for all water sources on the site, such as stormwater, graywater, and onsite water, and note opportunities for using that water for interior water use and or irrigation. 


  • Calculating outdoor water use is not required for this prerequisite . However, understanding how indoor water use compares to outdoor water use can help you gauge where to focus reduction efforts for the greatest benefit. Some water saving strategies address both indoor and outdoor water needs holistically. For example, graywater from interior sink fixtures can be collected for landscape irrigation.


  • Graywater used for landscaping cannot be calculated for this prerequisite, but can be counted in WEc1: Water Efficient Landscaping.


  • Are composting toilets an option? While not common, composting toilets can go a long way toward achieving this prerequisite. They affect programming and layout, so consider them early.


  • Consider setting water-reduction goals higher than the 20% reduction required by this prerequisite. Many projects are able to achieve 30%–40% savings with little or no impact on cost. First-time costs for water savings above 20% can be minimal since project teams will already be integrating water-saving techniques for this prerequisite.

Schematic Design

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  • Estimate the project’s baseline water needs and determine the baseline water use budget for indoor water use. This helps determine where the most effective water-saving technologies can be applied.


  • Establish goals for water use reduction and include these goals in the Owner’s Project Requirements (OPR) for EAp1: Fundamental Commissioning. Consider aiming higher than a 20% reduction. Many of the same strategies used for this prerequisite will also apply to WEc2: Innovative Wastewater Technologies and WEc3: Water Use Reduction.


  • Determine the numbers and types of occupants in the building. The water use calculation is based on occupant use and the number of full-time equivalent (FTE) occupants, including employees and visitors, not the number of water fixtures installed.



  • Determine user groups for the various fixtures as not all occupants may be using all the fixtures; for example, employee restrooms and customer toilets in a retail store will have different use patterns.


  • The baseline for commercial lavatory faucets has been changed in LEED 2009 to 0.5 gpm.  The previous baseline for commercial lavatory faucets was 2.5 gpm. Take note of this more stringent requirement compared with earlier versions of LEED.


  • This prerequisite only includes core water uses—bathroom lavatories, water closets, urinals, showers, kitchen faucets and pre-rinse sprays. Janitors’ sinks, pot fillers, and tub faucets can be left out as they are used to fill containers with a fixed water volume regardless of the flow rate. "Kitchen sinks" includes all sinks in public or private buildings that are used with patterns and purposes similar to a sink in a residential kitchen. Break room sinks would be included; commercial kitchen sinks are not included. Lavatory faucets refer to hand-washing sinks, regardless of location, but lab or healthcare sinks with regulated flow rates are excluded. Pot-filling sinks can be excluded.


  • Appliance and process water uses such as clothes washers, dishwashers, cooling tower make-up, and others, do not need to be included in the LEED water reduction calculations.  However, teams do have the option of earning an additional point for reduced appliance and process water as part of an exemplary performance point, building on the 30%–40% water-use reduction for WEc3: Water Use Reduction.


  • Well water and pond water are not considered “reused” water for the purposes of this credit and must count as potable water—so you don’t get credit for substituting them for conventional water sources. Water types that do count as reused are: graywater (lavatory, sink and shower water), rainwater, treated wastewater, air-conditioner condensate, reverse-osmosis reject, and sump-pump water.

Design Development

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  • Select water-efficient fixtures and strategies. Gather information on applicable fixtures including manufacturer, model number, and flush or flow rates.


  • For residential projects, showers typically use more water than any other fixtures due to the duration of use. For commercial projects, toilets and urinals typically use more water. Water-saving strategies should target the most consumptive fixtures to achieve greatest water reductions.


  • Compare the baseline and design case water use budgets to determine the water reduction percentage goals for the project. The LEED Online credit form has a built-in calculator to facilitate this calculation. Repeat this process until final selection of water fixtures and strategies have been made and the project’s water reduction goals are satisfied. 


  • Size graywater and rainwater systems to match non-potable water demand, for needs such as toilet flushing, cooling tower makeup, and irrigation.


  • Untreated rainwater, graywater, and blackwater may corrode plumbing systems, or lead to biological growth. Teams should plan for water treatment, filtration, or using corrosion-resistant materials. The use of seawater for toilet flushing, although very uncommon, can cause similar problems.


  • Plumbing piping must be doubled for interior water fixtures when graywater or rainwater is reused in addition to potable water. This is likely to add upfront costs, while potentially reducing water and sewer charges.


  • Sensors on toilets and faucets are perceived as saving water. However, several studies have shown that while they may offer some hygiene or other operational benefits, they increase water use substantially, due to “phantom flushes” and faucets running longer than needed. If you do choose lavatory sensors, look for models with adjustable flow durations. Although the LEED calculation estimates a standard 30-second use, setting the flow duration to a shorter time interval can help save water. In other words, adjusting the LEED design case calculation to a more accurate (and shorter) flow duration can help you meet the 20% reduction.


  • Aerators are very cost-effective, costing only a few dollars per fixture. Installing an aerator allows you to chose the sink fixtures that are desired and not have to worry if they are low–flow—simply purchase compatible aerators in addition to the fixtures. You can also easily retrofit existing faucets with low-flow aerators.


  • Many commercial toilets can be retrofitted with dual-flush flushometers, costing less than installing new dual-flush toilets. Check with manufacturers for retrofitting compatibility.

Construction Documents

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  • Integrate efficient water fixture specifications into construction and design development documentation.


  • Specify signage for water strategies that may require special instructions for use. This may include occupant signage for operating dual-flush toilets, indicating non-potable water, and operational signage for distinguishing pipes carrying reused water.


  • If reusing graywater or rainwater, ensure that key system components such as treatment and cisterns are not removed during value engineering.


  • Fill out the LEED Online credit form and upload water fixture cut sheets to LEED Online.


  • You must use an Alternative Compliance Path to document savings from a non-potable source in LEED Online. Adjust the design case total water use volume to account for the annual amount of non‐potable water. Then use the adjusted design case total water use to recalculate the percent reduction of water use for all fixtures. Additional documentation or calculations may include but are not limited to plumbing drawings, calculations and system capacity to support quantities provided, and any analysis to confirm the availability of the non‐potable water source.

Construction

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  • The contractor ensures that the correct fixtures have been purchased and any applicable water reuse systems or specified metering systems have been installed. 


  • Make sure supply pipes carrying non-potable water are clearly labeled and color-coded to avoid inadvertent cross-connection with potable water lines.

Operations & Maintenance

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  • Apply for water-reduction incentives and rebates through municipal water authorities.


  • Provide building managers with manuals for all irrigation systems and controls, fixtures and fittings, water-reuse technologies, on-site water treatment systems, and unconventional products.


  • Consider installing permanent water metering for ongoing monitoring of the project’s water use. A sub-metering system can help operations staff detect problems early and facilitate future LEED-EBOM certification.


  • Train cleaning and operations staff to maintain atypical fixtures such as waterless urinals, water sensors and other fixtures.

  • USGBC

    Excerpted from LEED 2009 for New Construction and Major Renovations

    WE Prerequisite 1: Water use reduction

    Required

    Intent

    To increase water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems.

    Requirements

    Employ strategies that in aggregate use 20% less water than the water use baseline calculated for the building (not including irrigation).

    Calculate the baseline according to the commercial and/or residential baselines outlined below1. Calculations are based on estimated occupant usage and must include only the following fixtures and fixture fittings (as applicable to the project scope): water closets, urinals, lavatory faucets, showers, kitchen sink faucets and pre-rinse spray valves.

    Commercial Fixtures, Fittings, and Appliances Current Baseline (Imperial Units) Current Baseline (Metric units)
    Commercial Toilets 1.6 gallons per flush (gpf)*

    Except blow-out fixtures: 3.5 (gpf)
    6 liters per flush (lpf)

    Except blow-out fixtures: 13 lpf
    Commercial Urinals 1.0 (gpf) 4 lpf
    Commercial Lavatory (Restroom) Faucets 2.2 gallons per minute (gpm) at 60 pounds per

    square inch (psi), private applications only (hotel

    or motel guest rooms, hospital patient rooms)

    0.5 (gpm) at 60 (psi)** all others except private

    applications

    0.25 gallons per cycle for metering faucets




    8.5 liters per minute (lpm) at 4 bar (58 psi),

    private applications only (hotel or motel guest

    rooms, hospital patient rooms)

    2.0 lpm at 4 bar (58 psi), all others except

    private applications

    1 liter per cycle for metering faucets




    Showerheads 2.5 (gpm) at 80 (psi) per shower stall **** 9.5 lpm at 5 bar (58 psi)
    For projects with commercial pre-rinse spray valves, the flow rate must comply with the asME a112.18.1 standard of 1.6 gpm or less.


    Residential fixtures, fittings, and appliances Current baseline (imperial units) Current baseline (metric units)
    Residential toilets 1.6 (gpf)*** 6 liters per flush (lpf)

    Except blow-out fixtures: 13 lpf
    Residential lavatory (bathroom) faucets 2.2 (gpm) at 60 psi 4 lpm

    8.5 lpm at 4 bar (58 psi), private applications only

    (hotel or motel guest rooms, hospital patient rooms)

    2.0 lpm at 4 bar (58 psi), all others except private

    applications

    1 liter per cycle for metering faucets




    Residential kitchen faucet
    Residential showerheads 2.5 (gpm) at 80 (psi) per shower stall**** flow rate ≤ 6.1 lpm

    (no pressure specified; no performance requirement)
    * EPAct1992 standard for toilets applies to both commercial and residential models.

    ** in addition to Epact requirements, the american society of Mechanical Engineers standard for public lavatory faucets is 0.5 gpm at 60 psi (2.0 lpm at 4 bar (58 psi)) (asME a112.18.1-2005). this maximum has been incorporated into the national uniform plumbing Code and the international plumbing Code.

    *** EPAct 1992 standard for toilets applies to both commercial and residential models.

    **** residential shower compartment (stall) in dwelling units: the total allowable flow rate from all flowing showerheads at any given time, including rain systems, waterfalls, bodysprays, bodyspas and jets, must be limited to the allowable showerhead flow rate as specified above (2.5 gpm) per shower compartment, where the floor area of the shower compartment is less than 2,500 square inches (1.5 square meters). for each increment of 2,500 square inches (1.5 square meters) of floor area thereafter or part thereof, an additional showerhead with total allowable flow rate from all flowing devices equal to or less than the allowable flow rate as specified above must be allowed. Exception: showers that emit recirculated nonpotable waterNonpotable water: does not meet EPA's drinking water quality standards and is not approved for human consumption by the state or local authorities having jurisdiction. Water that is unsafe or unpalatable to drink because it contains pollutants, contaminants, minerals, or infective agents. originating from within the shower compartment while operating are allowed to exceed the maximum as long as the total potable water flow does not exceed the flow rate as specified above.




    The following fixtures, fittings and appliances are outside the scope of the water use reduction calculation:

    • Commercial Steam Cookers
    • Commercial Dishwashers
    • Automatic Commercial Ice Makers
    • Commercial (family-sized) Clothes Washers
    • Residential Clothes Washers
    • Standard and Compact Residential Dishwashers

    Potential Technologies & Strategies

    WaterSense-certified fixtures and fixture fittings should be used where available. Use high-efficiency fixtures (e.g., water closets and urinals) and dry fixtures, such as toilets attached to composting systems, to reduce water demand. Consider using alternative on-site sources of water (e.g., rainwater, stormwater, and air conditioner condensate) and graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. for nonpotable applications such as custodial uses and toilet and urinal flushing. The quality of any alternative source of water used must be taken into consideration based on its application or use.

Technical Guides

Energy Policy Act of 1992 and amendments

Pages 62-69 of this legislation set federal standards for plumbing fixtures.


Energy Policy Act of 2005

The Energy Policy Act (EPA) addresses energy production in the United States. One example, the Act provides loan guarantees for entities that develop or use innovative technologies that avoid the by-production of greenhouse gases.


LEED 2009 Water Use Reduction: Additional Guidance

This document from USGBC offers guidelines to help you properly set up fixture usage groups in the LEED Online credit form, avoiding common mistakes associated with the water-efficiency prerequisite and credit.

Web Tools

WATERGY version 3.0

WATERGY is a spreadsheet model that uses water/energy relationship assumptions to analyze the potential of water savings and associated energy savings.


EPA Water Information links

This website offers links to state and regional water information.


Water Studies

This site provides a number of studies related to water.

Organizations

Alliance For Water Efficiency

AWE advocates for water-efficient products and programs and provides information related to water conservation.


EPA Office of Water

The Office of Water coordinates EPA's efforts to protect drinking water, oceans, watersheds and other aquatic ecosystems.


American Rainwater Catchment Systems Association

This organization promotes rainwater catchment in the U.S.


Oasis Grey Water Policy Center

Oasis Design, a maker of graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. systems, maintains this compilation of graywater laws and other resources on the regulation of graywater use.

WEp1 LEED Online Form

This sample form for WEp1 is from a real project whose name was changed on the form. (Note that WEp1 was achieved for this project even though this sample displays that the form was not completed.)

Product Cut Sheets

Carefully research products and examine cut sheets to find fixtures and fittings meeting the credit requirements, as shown in these examples.

LEED Online Forms: NC-2009 WE

The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 WE credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.

Version 4 forms (newest):

Version 3 forms:

These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions on these forms; for more information, visit LEED Online and click "Sample Forms Download."

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

602 Comments

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Christine Harvey
Oct 17 2014
Guest

Pot washing sink

Project Location: United States

I saw a comment on this site that implied the water used for pot washing sinks and kitchen food prep sinks can be excluded from the calculations, can someone verify that for me? I don't see anything to back that up in the credit form or the LEED Reference Guide. Thanks!

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Michelle Rosenberger Partner, ArchEcology, LLC Oct 20 2014 LEEDuser Member 5447 Thumbs Up

Hi Christine,
Yes, excerpt from a Proven Provider presubmittal call "kitchen hand sinks that are used for food prep, wash down or cleanup (including handwashing due to these activities) should be excluded as process waterProcess water is used for industrial processes and building systems such as cooling towers, boilers, and chillers. It can also refer to water used in operational processes, such as dishwashing, clothes washing, and ice making.. If the sink runs through a grease interceptor, it can be excluded as a process water use. If the hand sink is used primarily for hand washing or similar to breakroom kitchen sink, it can included as a kitchen sink regardless of grease interceptor."

Post a Reply
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Shenhao Li Atkins
Oct 14 2014
Guest
271 Thumbs Up

How to calculate Squatter Toilet in we p1? and roof garden?

Project Location: China

HI, i have 2 questions to ask:
1.Now i have a hotel project in china. In this project, Several squatter toilets(with water tank) are designed and will be constructed in the future. But i can`t figure out which fixture family is more appropriate for it as the baseline(water closet or blow-out)?
Also i want to know the exactly definition of blow-out fixture.

2. Also in this project. Our client will build a roof garden. Some areas of roof garden is vegetated roof, and other area will be construct as lane, tennis court or other things. These areas are paved by wood, pebble,tiles instead of traditional roof material(paints, concrete etc.). Can we treat these parts as vegetated roof? Or equivalent SRI for these parts by material color is more acceptable? If we equivalent SRI for this parts, is it acceptable i upload a test report or cut sheets of the equivalent material? (For example, if i have a pavement constructed by green tiles, and we know the SRI of green paints is 21, can we submit the SRI of green tiles as 21?)

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Carlie Bullock-Jones, LEED Fellow Principal, Ecoworks Studio Oct 14 2014 LEEDuser Expert 2558 Thumbs Up

Hello Shenhao -

1. Check out the USGBC's Water Use Reduction Additional Guidance document found here for information on blow-out fixtures - http://www.usgbc.org/Docs/Archive/General/Docs6493.pdf

2. Be sure to post your inquiry #2 under the SSc7.2 section of LEEDuser for feedback.

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Razan Nejem Environmental Engineer, LEED AP BD+C
Sep 17 2014
Guest
318 Thumbs Up

LEED male/female 50/50 gender ratio

Hi Everyone,

Regarding one of the FAQ's above in the birds eye view section with regards to gender ratio. I once received a comment from GBCI on a project stating the following
"The current staffing level is not an acceptable rationale for deviating from the standard usage ratio of 50/50 M/F. The calculations require a balanced, one-to-one sex ratio unless project conditions exist (such as a male dormitory) which would affect the gender ratio for the life span of the building and warrant an alternative ratio. "

hope that helps

Post a Reply
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Omar Katanani
Sep 05 2014
LEEDuser Member
8021 Thumbs Up

Discrepancy in graywater volume between Engineer & ELED

Dear all,

We are consulting for a big retail shopping mall. The project is aiming to achieve this prerequisite and the WEc3 by installing sanitary fixtures close to the baseline values, but complementing it with a full graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. recycling system which will collect water from all lavatories and kitchen sinks (non-greasy water of course).

The Mechanical Engineer performed calculations based on typical projects of the same size / type, and calculated around 200 cubic meter of graywater recycled per day.

We did the same calculations as per the LEED guidance , and found that the total amount of graywater is around 20 cubic meter per day (almost 10% of the Engineer's estimated value). We assumed the same flow rates of lavatories / sinks, but it seems that the Engineer has assumed more uses and also included water consumption for activities which LEED doesn't take into consideration (washing food in restaurants, water for cleaning the floor, etc).

My question is:
If I provide sufficient calculations by the Mechanical Engineer to the USGBC, would this be enough to assume the Engineer's graywater volumes in the LEED Credits? If I use the Engineer's numbers, I would be able to achieve the full 4 credits of WE Credit 3 (plus 1 ID point), in addition to the 4 credits of WE Credit 1 (Water Efficient Landscaping) as no potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. would be used for irrigation.

Anyone had a previous experience of a similar situation?
Thanks!

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Jean Marais b.i.g. Bechtold DesignBuilder Expert Sep 05 2014 LEEDuser Member 8705 Thumbs Up

I've not checked this for a while, but I must caution not to lump credit requirements together. For the prerequisite, you may only account for those elements listed and still must reach the minimum...that means regardless your greywater use, you still must have efficient taps, etc.

For greywater calcs. I think the engineer's numbers are good to use if you include them with a narritive.

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Omar Katanani Sep 05 2014 LEEDuser Member 8021 Thumbs Up

Thanks Jean,

Looking at the USGBC's "Water Use Reduction Additional Guidance" version 8 (pages 4 & 5), and quoting the below:

***
"Overall, the focus of Water Use reduction prerequisite and credit is water efficiency of the installed fixtures and fixture fittings regardless of the water source, but projects are still allowed to use on-site alternative sources of water to achieve water use reduction through an alternative compliance path.

Examples of on-site non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. sources that apply to the Water Use Reduction prerequisite and credit include: graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area., captured rainwater, air conditioner condensate, cooling tower blow-down/bleed-offBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup. water...

To document the use of on-site non-potable water to reduce water use for flush and flow fixtures, use the Alternative Compliance Path (ACP) section of the applicable LEED Online forms, WEp1 and/or WEc3"
***

Back to my initial question:
Can we consider the Engineer's estimated collected graywater volume from usages such as commercial kitchen sinks (which are not included for LEED purposes), knowing that the while the baseline scenario does not account for these volumes? I do not see why we can’t do it, as we need to be realistic and reflect the actual design / actual consumption rates in our calculations: the graywater system will be operational and will provide water to cover 100% of the WC flushing demand and 100% of the irrigation demand. So why not explain this to the USGBC?

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Michelle Rosenberger Partner, ArchEcology, LLC Sep 05 2014 LEEDuser Member 5447 Thumbs Up

Hi Omar,
We have a project that is using captured rainwater to offset WC flushing and irrigation. And we are using the alternate compliance to document additional reduction in WEcr3. Though our source is rainwater and not greywater, the issue would be the same I believe. The non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. source is not directly part of the baseline vs. proposed fixtures calculation. It is solely a calculated volume that you use as an additional input to modify the results of WEpr1 and WEcr3.

I do not believe your greywater sources need to match up with the low flow fixtures regulated by the WE credits, and I don't see why you would not use the Engineer's greywater calcs to establish your annual non-potable volumes, just like we are using the civil's cistern calcs to establish ours. Obviously profuse explanations are always a good idea. If you are a Proven Provider, you can always confirm this in a presubmittal call. Good luck.

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E&Z LEED Consulting Director of Sustainability Edwards & Zuck
Aug 06 2014
LEEDuser Member

Dual Shower Heads in Luxury Hotel Suite

My project, a luxury hotel, wants to put multiple shower heads in their presidential suite. Is there a maximum number of flowing fixtures allowed in a shower so long as all components when on do not exceed 2.5 gpm?

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Kathryn West LEED AP BD+C, O+M, Green Globes Professional, Guiding Principles Compliance Professional, Energy Ace Aug 06 2014 Guest 3328 Thumbs Up

There is not a maximum number of flowing fixtures allowed. However, to follow the intent of the credit I'd recommend that you augment the credit form to account for the fact that any showers taken in the presidential suite will actually be more like multiple showers. It might be as easy as bumping up the total daily uses. Are the showers throughout the building 2.5 gpm or just in the presidential suite? There may be a LEED interpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. about this but I don't see anything in the Water Use Reduction Additional guidance.

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E&Z LEED Consulting Director of Sustainability , Edwards & Zuck Aug 07 2014 LEEDuser Member

Thank you Kathryn. All the showers throughout the building will be 2.5gpm or lower to get us to meet the minimum reduction required.

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Kathryn West LEED AP BD+C, O+M, Green Globes Professional, Guiding Principles Compliance Professional, Energy Ace Aug 07 2014 Guest 3328 Thumbs Up

I'd add a description for your LEED reviewer and either bump up the total daily uses or create a separate "fixture group" for the presidential suite. I found this LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. but it was for LEED for Homes:

Inquiry: How should the shower flow rate be calculated if there are two fixtures serving one stall?

Ruling

If one stall has two fixtures that cannot be operated simultaneously (e.g., a showerhead and a handheld wand where only one can be operated at one time), the flow rate for the purposes of the credit should be the higher of the two. If one stall has two fixtures that can be operated simultaneously (e.g., dual showerheads that can both be operated at the same time), the flowrate for the stall is the sum of both fixtures.

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GBC Council CL Chile GBC
Aug 06 2014
LEEDuser Member
44 Thumbs Up

Pressure of Showers in a residential building

Hi! We have a data sheet from a shower which specifies a flow of 7,8 liters/minute at a pressure of 5.5 kgf/cm2 (which is equivalent to 5,39 Bar or 78 PSI). The problem that we have is that we are not sure if presenting this information with 78 psi instead of 80 will mean a problem for the reviewer or if neccessarily we will have to make a convertion (adjust the flow to 80 PSI) which in our case is very difficult as we don't know hoy to do it (for flow convertions related to pressure adjustments, calculations are not as simple as a cross multiplication or a proportion). Has any one had a similar experience?. Thanks so much for any help provided. Regards,

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Michele Helou Principal Sage Design & Consulting
Jul 23 2014
LEEDuser Member
817 Thumbs Up

Visitor Usage Rates and Dual Flush Fixtures

We have several unisex restrooms with dual flush toilets at a library. We assume some percentage of visitors use these restrooms, and another percentage use the group restrooms (with urinals). This means that some men will be using the df toilets for liquid waste at a half flush.

It appears that the LEED RG usage chart assumes for male visitors there would be 4 trips to the urinal for every 1 trip to the WC.
So tell me, why can't I use this ratio to figure out the dual flush average?

The Additional Guidance Document states 2:1 for residential (not sure why there either). But for visitors - can we use a 4:1 average on the DF toilets?

It seems like I can break the calculation out differently to not use the DF average at all - and just count flushes.

Anyone?

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Charles Nepps Jul 23 2014 LEEDuser Member 181 Thumbs Up

For women's restrooms with DF toilets you use the weighted average, so I see no reason you cannot make the same assumptions for Unisex restrooms with DF toilets and no urinals.As long as you can defend your percentages regarding how many men will use which type of restrooms, you should be fine.

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EBRU UNVER LEED AP BD+C
Jul 23 2014
LEEDuser Member
139 Thumbs Up

lab sink, kitchenette sink and shower water calculation rate

We are working on NC Office Building Project.
The building has 6 lab sinks, 3 kitchenette sinks and 9 showers (for guests, will be used maybe ones a week).
Should we include to the calculation?
How we can calculate the water usage rates?
Thank you,

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Charles Nepps Jul 23 2014 LEEDuser Member 181 Thumbs Up

The usage is driven by the FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. (from PIf3) numbers, so you need to be sure you have those correct. You 'll find that for "general office" space no transients are assumed, but you must make an educated guess at the number of visitors expected and include those numbers on WEp1 form, or it will be rejected by the USGBC during review.

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EBRU UNVER LEED AP BD+C Jul 24 2014 LEEDuser Member 139 Thumbs Up

Thank you Charles,
I will check the PIF3 form.
Unfortunately it not easy to predict the usage rate for the guests.
Do you have any idea for the lab sink and kitchenette sinks (will be use at the cafeteria and service area).
Thank you again,

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Charles Nepps Jul 24 2014 LEEDuser Member 181 Thumbs Up

By "cafeteria" do you mean an area where food will be prepared and served/sold to employees and visitors, or do you mean more of a breakroom situation? If part of the office building is designated as an operating cafeteria, you will need to identify that on the PIf3 form in Table 1 and Table 4. I would assume kitchenette sinks would have the same usage rate as kitchen sinks and you should only consider FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories., no transients. I'm a bit unclear about the lab sinks, what exactly will their purpose be?

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EBRU UNVER LEED AP BD+C Aug 01 2014 LEEDuser Member 139 Thumbs Up

To be more clear, there will be 3 cafeterias: 1 where food will be served, 1 in the shelter (to be use in case of emergency) and the last one is for break room.
There are also 6 lab sink, however we can not predict the usage rate.
What you can advise me, how should I calculate the water consumption?
Thank you

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Charles Nepps Aug 01 2014 LEEDuser Member 181 Thumbs Up

Just to clarify further, do you mean “lab” as in laboratory sink or “lav” as in lavatory sinks (hand washing sink)? The reason this is important is “lab” sinks do not need to be considered in the water reduction calcs, however “lav” sink do.

Break room kitchen sinks would be accessible to all office workers, so basically you’ll need to assume 1 use per day per FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories.
The “emergency shelter” sinks can be ignored, depending on your definition of emergency. If it‘s for use in case of, say, natural disaster, and not simply when the regular cafeteria is too busy, than it’s safe to ignore the water usage there. You should include a narrative explaining that the fixtures in this area are only for emergency use, and perhaps give examples of what would constitute an emergency.
The operating cafeteria is a bit more difficult. If the kitchen sink is equipped only with a commercial pre-rinse spray valve, then you merely need to show that the spray valve complies with ASME A112.18.1 standard of 1.6 gpm or less; it does not need to be included in the reduction calcs. If the sink is used primarily for filling pots, washing produces, etc., that’s all considered process waterProcess water is used for industrial processes and building systems such as cooling towers, boilers, and chillers. It can also refer to water used in operational processes, such as dishwashing, clothes washing, and ice making., which also does not need to be considered in the calculations. If the sink is there primarily for hand washing, then you need to make some educated guesses about the usage based the cafeteria’s hours of operation and number of staff working there. I haven’t found any USGBC guidelines regarding usage rates in these types of situations, but if someone else out there has, please jump in and correct me.

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MERVE OKUMUŞ architect iltay mimarlık
Jul 23 2014
LEEDuser Member

WEp1 ,What are the ratio of kitchen sink and shower ?

İn our project the kitchen sink and shower are not used by all FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. and visitor,
What percentage I may use for these fixtures, and what are the ratios?
Thank you

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Charles Nepps Jul 23 2014 LEEDuser Member 181 Thumbs Up

The assumption normally is all FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. have equal access to things like kitchen sinks. Fixtures like WC, Urinals, and Showers can be designated male or female only, and those ratios are normally 50/50. Without knowing your particular situation, you would probably have to provide a narrative explaining why the kitchen sinks are not used by all FTE.

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Juliane Muench
Jul 21 2014
LEEDuser Member
684 Thumbs Up

Proces water / include oven?

Hi! I am working on a retail project that does not contain any of the following process equipment: Commercial cloth or dishwasher, Ice machine, food steamer or combined oven.
We only have two small bake-off ovens without microwave function (therefore not combined). Do I have to include the bake-off ovens into the water calculations?
Thanks.

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Charles Nepps Jul 23 2014 LEEDuser Member 181 Thumbs Up

I would think the water supplied to the bake-off ovens would be considered process waterProcess water is used for industrial processes and building systems such as cooling towers, boilers, and chillers. It can also refer to water used in operational processes, such as dishwashing, clothes washing, and ice making., therefore not calculated, but that's purely a guess.

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Anu Sumanth Architect | LEED AP Hayes Group
Jul 09 2014
LEEDuser Member
224 Thumbs Up

Appealing WEp1

We have a small two story core and shell project. The owner provided rough ins for plumbing fixtures to be installed by the tenant. We had a Lease agreement and tenant guidelines that outlined the necessity for water savings fixtures. We tried to take a performance approach and GBCI rejected our documentation. For the appeal, I am planning to take a Tenant Neutral approach, if that is the case all the fixtures would be just baseline and I will not get the required 20%. The jurisdiction that we are in requires all first time to be LEED certified minimum so the Tenant has installed water conserving fixtures and waiting to get their TI portion LEED certified. They cannot proceed until the shell is Certified. I am planning on uploading their TI installation as supplemental information and all the City's ordinance. I want to make sure this is adequate, I don't want the appeal to be rejected.

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Amit Ahiel Jul 23 2014 Guest 176 Thumbs Up

Hi Anu,

Can you provide some context:
What was the reviewer comment?
What was the reviewer's technical advice?
What was the lease agreement requirement for water savings: 20% per WEp1?

Your question is lost and some words seem missing, for example "The jurisdiction that we are in requires all first time to be LEED certified minimum"....first time what?

Would love to help but need more information.

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Malek Abualhaj
Jun 30 2014
LEEDuser Member
17 Thumbs Up

Flow Restrictors

Hello, we have non compliant faucets and showerheads, therefore, we are going to install flow restrictors. Would we need to test them at 60 and 80 psi? the whole building has a pressure of 3 bar (43 PSI).

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Maria Isabel Conde Owner Aqua Terra (Panama) S.A.
Jun 23 2014
LEEDuser Member
38 Thumbs Up

Hotel guests

Hi,

For an hotel. How can we count the guests?. Residents, FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories., or visitors/transients?.

Thanks!

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Kristina Bach Sustainability Specialist Jun 23 2014 LEEDuser Member 976 Thumbs Up

Hotel guests should generally be entered as residents. There is a LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. out there which indicates how these should be calculated:
http://www.usgbc.org/leed-interpretations?keys=100001771

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Jens Apel Jun 24 2014 Guest 917 Thumbs Up

This was as well covered in an addendum of November 2011:
For hospitality projects, FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. and transient occupants are calculated per the typical methodology for the respective occupancy types.
Hotel guests may be determined based on the number and size of units in the project. Generally, assume 1.5 occupants per guest
room and multiply the resulting total by 60% (average hotel occupancy per AH&LA information) to determine the total number of hotel
guests. Alternatively, occupants may be derived from actual historical occupancy numbers. Fixture use assumptions for hotel guests
follow the fixture assumptions for residential occupants. Accordingly, lavatories located in guest rooms are considered to be private lavatories. Additionally, day use guests at the hotel should be included in the value for transient / visitor occupants. Per typical fixture use assumptions, this category of occupants assumes zero shower uses throughout the day. Example: 123-room hotelTotal Hotel Guests = 123*1.5 * 60%Total Hotel Guests = 111

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Saud Abdul Rasheed LEED Engineer Al Yamama Company
Jun 14 2014
LEEDuser Member
249 Thumbs Up

Documenting On Site Water Reuse

Hello All,

In our Project we are installing a Water Treatment Plant where we are collecting grey water from sinks as well as capturing rain water and treating them and using them in the flushing of toilets in the building. The total daily capacity of the plant is 50 m³ i.e. 13.2 kGal.

I have gone through the Water Use Addition Reduction Guide and I am aware that these calculations should be used in the Alternative Compliance Path but I cannot understand how will we make the actual calculation. When I check leedonline forms for WEc1 and WEc3 I cannot find a place where I can subtract the adjusted total fixture water use annual volume performance case from Total calculated fixture water use annual volume baseline case. Where can I subtract the quantity of non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. use for flush fixtures? How can I do this calculation and where do I fill it in the leedonline form?

Pleas advice.

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Michelle Rosenberger Partner, ArchEcology, LLC Jun 14 2014 LEEDuser Member 5447 Thumbs Up

Hi Saud,
You take credit for it in WEcr2, but you do have to make 50% reduction in wastewater. We have a project with a cistern that is going to supply irrigation water and toilet flushing. WEcr3 is only about the total water reduction by virtue of low flow fixtures. But it does feed your WEcr2 calculation, so the lower the toilet fixtures the better. For toilet flushing, you would use WEcr2 and input your non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. volume. For WEcr1, should you be irrigating with it, you would also simply input the non-potable volume into the form.

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Saud Abdul Rasheed LEED Engineer, Al Yamama Company Jun 15 2014 LEEDuser Member 249 Thumbs Up

Dear Michelle,

1) What I understand is that we will get credit only in WEc2 then? The water savings from the treatment plant will be added and filled in WEc2 form.

But again wont this water add in the percentage of water savings in WEp1 and/or WEc3 as we are treating water (obviously giving us points in Innovative Wastewater Technologies) but at the same time we are using this water as non potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. for flushing (reducing potable water consumption in WEp1 and WEc3)?

2) I have a second question is how will I document the treated water annual voluem? 13.2 KGal is the volume of capacity of the plant. So in one day this can be the maximum water treated. How can I know how much water will be treated on a daily basis from flushes which may vary from day to day?

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Michelle Rosenberger Partner, ArchEcology, LLC Jun 15 2014 LEEDuser Member 5447 Thumbs Up

Hi Saud,
Yes, as I understand it credit for the reduction is only in WEcr2. In WEp1/c3, you are calculating "total" water reduction and not distinguishing between whether it is potable or not. LEED would still like to reduce demand first and foremost. That is why for example in WEcr1 about irrigation, you still have to make the 50% reduction in total water use even if you are using non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. to get the 4pts.

On the calculation, flushes don't vary because LEED gives you the daily use expectation. 3x each FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. user per day unless you have urinals, in which case it's 1x for men + 2x urinals + 3x for women. Visitors are also included of course. So fill out WEpr1/cr3 first with your low flow fixtures. The wastewater daily use volume from your toilets and urinals is going to feed into the WEcr2 form. If your plant capacity is greater than the wastewater volume you need on any given day, you would simply plug in the 100% wastewater value.

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Michelle Robinson Re:Vision Architecture Jun 16 2014 LEEDuser Member 704 Thumbs Up

It's my understanding that you cannot take credit for the graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area./rainwater in WEp1 (per Addenda from 7/9/2010). However, per USGBC's Water Use Reduction Additional Guidance document (http://www.usgbc.org/resources/water-use-reduction-additional-guidance) you should be able to include it in WEc3 since you're reducing the amount of potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. needed for the regulated fixtures required to be included with this credit. And as Michelle Rosenberger said, you can also take credit under WEc2.

Once you determine how much graywater/rainwater you'll be able to use (i.e. what you'll have available based on the sink flow rates and the daily rainfall throughout the year combined with the plant capacity and cistern capacity) you subtract that total annual volume from the total annual volume consumed by the fixtures.

You might want to take a look at the LEED v2.2 Credit Form for where to subtract the volume (http://www.usgbc.org/sampleforms/v2) and either upload it or use it to check to see how the math is performed for your alternate compliance path. The v2.2 Form includes the basic math already to account for a given volume of graywater and rainwater use. Just make sure you're using the correct flowrates and durations for the baseline case (and remove the janitor sink) per v2009, since some of them have changed. (And if you're using metering faucets, it'll be a bit of a hassle to convert them to the v2.2 form...)

You also might find more info on LEEDuser under the WEc3 credit since that's where you should be allowed to take credit for the rainwater as well. (There may be some guidance there about whether or not you'll need to do calculations for the full year on a daily basis with actual historical rainfall data since some days you'll get more rain than others or if you can make some assumptions/generalizations...)

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Saud Abdul Rasheed LEED Engineer, Al Yamama Company Jun 16 2014 LEEDuser Member 249 Thumbs Up

Michelle Rosenberger,
Michelle Robinson,

Thank you so much for your replies and detailed explanations. I did all the calculation for the flow fixtures and flushes. I still cannot figure how to make calculations for the treatment plant.

Also there is still one problem. In the LEED BD+C CS 2009 forms I cannot find any table or calculation for non potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. in WEc3. For WEc2 there is a place to add non potable water but for WEc3 there is only the calculation tables for flows and flushes. I want to use this treated grey water and include it in the WEc3 but I cannot find where to do this math in the form?

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LEED Consultant Green Building and Alternative Energy
May 21 2014
LEEDuser Member
1485 Thumbs Up

Buildings with no water use

Hello,
I am working on a Campus project and some of the buildings do not require use of water because near buildings satisfy the occupants needs. My doubt is about the Leed InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10214. It mentions "eligible" water fixtures, does "eligible" refers to "applicable"? Does the interpretation may apply to my project? Thank you in advance.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jul 26 2014 LEEDuser Moderator

Yes, eligible and applicable basically mean the same thing here. It sounds like your project is exempt.

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Camill Marciniak Intep
May 15 2014
LEEDuser Member
267 Thumbs Up

All sanitary installations will only be built at tenant fit-out

We are working on the LEED Core&Shell (v3, 2009) project in Switzerland . The core&shell project does not include sanitary installations in the scope of work, which will only be built at tenant fit-out stage. Only the Core&Shell work is done by the owner. The tenant will rent the entire floor area and take over the entire tenant work. We have a C&S project with no signed tenants yet. The owner is providing no fixtures for the tenants in the base C&S project. The core and shell scope includes no fixtures (toilet/sink/shower). All fixtures are installed by the tenant. How can we comply with WEp1? We strive for no points for WEc3 Water Use Reduction.
Do we need a binding lease agreement that the future tenant will complete the build-out with 20% more efficient plumbing fixtures and fitting? The owner prefers to do without a binding lease agreement if possible.
Or are we exempt from WEp1 because our C&S project does not include any regulated plumbing fixtures?
I read already the Core and Shell Appendix 4 in the back of the LEED Building Design and Construction Reference Guide.
Thank you very much for your feedback!

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jul 26 2014 LEEDuser Moderator

Camill, I think CS Appendix 4 spells this out pretty clearly. If you're going to claim savings from tenant work you need a tenant sales or lease agreement.

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John Covello LEED AP BD+C, EBOM, LEED and Sustainability Manager Development Management Group
May 15 2014
LEEDuser Member
389 Thumbs Up

Rainwater capture artificial retention pond

Hello,

We are looking to use rainwater capture to provide for our site's sanitation and irrigation needs. There is no potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. actually available for the site currently from local sources. What documentation would we need about the rainwater capture when submitting it to LEEDonline?

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Carlie Bullock-Jones, LEED Fellow Principal, Ecoworks Studio May 15 2014 LEEDuser Expert 2558 Thumbs Up

Hello John,

The Water Use Reduction Additional Guidance document found on the USGBC website outlines information on how to document non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. use in this prerequisite.

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Ashwin Kumar Sustainability Services Consultant M+W Group
May 03 2014
Guest
23 Thumbs Up

Query Regarding use of Treated RO reject water from ETP for WEP1

We plan to use RO Reject Water which is generated from within the LEED project Boundary for a Factory Project (registered within a Master Site Campus) towards the Flushing requirement.
As mentioned in Under the Water Use Reduction (WE P 1, WE C3).Vide Addiotional Guidance Document dated Dec 1, 2009 (Updated April 1, 2013)Version 8.

However, direct use of RO Reject water in the plumbing lines for Flushing is not allowed becase of the high TDS loading etc.

So we plan to treat it through an Effluent Treatment Plant and re-use the treated water for Flushing Requirement. The Effluent Treatment Plant is located on the Project site.

Please affirm if this is applicable for gaining points under WE P1 and WE C3 and also for exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements.. (since we plan to meet the 60% reduction in potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. use for WE C 3)

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jul 26 2014 LEEDuser Moderator

Ashwin, this seems to me like a valid way to earn the credit, as it seems akin to graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. reuse, which is allowed.

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FABIO VIERO Head of Sustainability Manens-Tifs s.p.a.
Apr 19 2014
LEEDuser Member
542 Thumbs Up

Rainwater

Hi,

I'm now working on a project under LEED certification according to NC v2009.

We collect rainwater to provide non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. to wc.

May we consider this water in WEp1 and WEc3 calculation?

If the answer is yes, since this form does not allow to account it as WEc2, may we click on one of the two option related to "ADDITIONAL DETAILS" in order to upload a dedicated spreadsheet to justify it?

Thanks!

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Jens Apel Apr 22 2014 Guest 917 Thumbs Up

Fabio,
you can consider this in the calculations. See the document here: http://www.usgbc.org/resources/water-use-reduction-additional-guidance.
In a recent project with approved design review I uploaded the calcs and narrative in WEc2 and used the alternative compliance path text box in WEc3 to refer to WEc2 (WEp1 was achieved with low flow fixtures).

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FABIO VIERO Head of Sustainability Manens-Tifs s.p.a.
Mar 31 2014
LEEDuser Member
542 Thumbs Up

WC for disables

Hi,

we are working on an office building under LEED NC 2009 certification.

We have a question about WC dedicated to disables.

If a corporate policy specifies that WC for disables are used ONLY by disables and whatever use by other people is not allowed, may we exclude these WC from calculations about Water Efficiency?

Many thanks!

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Michelle Rosenberger Partner, ArchEcology, LLC Mar 31 2014 LEEDuser Member 5447 Thumbs Up

Hi Fabio,
My guess would be no, you cannot exclude them. When we have projects with ADA (disabled) fixtures, we use a separate fixture group and assign 5% of our FTEs to those fixtures. If you know the number of users for sure and you could prove it with backup, you could use that number.

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FABIO VIERO Head of Sustainability, Manens-Tifs s.p.a. Apr 01 2014 LEEDuser Member 542 Thumbs Up

Michelle,
Thank you!

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Noriko Yasuhara Woonerf Inc. Apr 17 2014 LEEDuser Member 1794 Thumbs Up

I have a follow up question related to ADA fixture groups.

In "A" building there are only water closets and no urinals available on the disabled toilets.
If the users cannot use urinals it seems fair to me to consider the disabled fixture group composed of 100% females and compare water closets against water closets. I know that USGBC guides for a 50/50 ratio of male/female users. How do you submit your documentation?

Thanks in advance.

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Michelle Robinson Re:Vision Architecture Apr 17 2014 LEEDuser Member 704 Thumbs Up

Yes, if there are no urinals in the restrooms, you'll compare WC usage to WC usage. You can still assume the 50/50 ratio, but both male and female FTEs (for this fixture group) will be assumed to use the WC three times a day. If they are dual flush toliets, one of the flushes would be large and two would be small flushes for each person. Since there are no urinals, you would have zero daily uses for a urinal in both the baseline and designed/installed cases.

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Melissa Merryweather Director, Green Consult-Asia Apr 17 2014 LEEDuser Member 2206 Thumbs Up

Yes, we had a similar case where one small group of people (tellers) used a separate w.c. with no urinal. On the submittal form you have to click the non-standard use box, put in your calculated uses, and submit a separate word doc or PDF in the uploads explaining why there is a non-standard number of uses for that fixture. Sounds complicated but is't really.

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Sheryl Swartzle LEED administration TLC Engineering for Architecture
Mar 21 2014
LEEDuser Member
695 Thumbs Up

Cruise Terminal FTE and Visitor/Transient count

Our cruise terminal has a season from October 1 to April 15 when the FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. will be 155 and visitor/transient will be 2,000 per day for 3 or 4 days per week (the other 3-4 days per week it would drop to 3 or 4 FTEs with 1 visitor/transient). From mid-April to end of September this drops to 2 to 3 FTEs and 1 visitor/transient per day. I think we should we use an average of daily FTE and visitor/transients for the year but would like to confirm. Your thoughts?

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Melissa Wrolstad Senior Project Manager, CodeGreen Solutions Mar 25 2014 LEEDuser Member 1930 Thumbs Up

If I were in your shoes - I'd run the calculator for both situations separately and see if you end up in the same credit threshold. If you do - include a narrative to let the reviewer know you ran both cases and either way you end up in the same threshold.

If you don't (which you may not given the very different ratio of FTEs/transients in the two different scenarios), either go with the more conservative results and provide a narrative explaining that you have been conservative, or see if you can get in touch with a GBCI representative - present a case to them for something you think is reasonable and get in writing that they approve (which hopefully they will!)

Best of luck,
Melissa

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Michelle Robinson Re:Vision Architecture Mar 25 2014 LEEDuser Member 704 Thumbs Up

You can always use a separate calculator for each of the different cases and then sum total it all up to show what the annual usage will be.

Download the WEp1 Sample LEED form, then fill it out and save it once for each of the usage patterns (being sure to cover the full year). Then create an excel spreadsheet as a summary -- enter one line for each usage pattern and a column each for flush fixture and flow fixture water use annual volume for both the baseline case and the performance case. (And maybe add a column at the beginning to explain what the usage pattern is.) Then have a totals section and calculate the percent reduction of water use. Basically you'll summarize all the gray rows on the LEED form in your excel spreadsheet.)

You will have to click the special circumstances box on the bottom of the LEED form and then upload all the sample forms and the excel summary sheet. (Include a brief narrative explaining your various usage groups and that you calculated them all separately and summarized it on the excel spreadsheet.) If you do all that in a clear manner, you shouldn't get questioned.

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Sheryl Swartzle LEED administration, TLC Engineering for Architecture Mar 26 2014 LEEDuser Member 695 Thumbs Up

Thanks to you both!

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Carlie Bullock-Jones, LEED Fellow Principal, Ecoworks Studio Mar 27 2014 LEEDuser Expert 2558 Thumbs Up

In the form Table WEp1-2 Fixture Groups Definition, consider creating separate fixture groups for the following scenarios you described, and include a narrative explaining your rationale:

- Fixture Group 1: 155 FTEs and 2,000 visitors - indicate the Annual Days of Operation based on 4 days per week between Oct.1 – April 15

- Fixture Group 2: 4 FTEs and 1 visitor - indicate the Annual Days of Operation based on 3 days per week between Oct. 1 – April 15

- Fixture Group 3: 3 FTEs and 1 visitor - indicate the Annual Days of Operation based on 7 days per week between April 15 – end of September

Hope helpful!

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Lisa Marshall Ecological Building Strategies
Mar 14 2014
Guest
48 Thumbs Up

ADA showerhead

Our project has 2 out of 10 shower stalls that are considered ADA shower stalls. They consist of having a fixed 1.0 gpm shower head and a diverter valve to switch to the 1.125 gpm hand held shower. How do we account for the difference in gpm on the WEp1 form for these two ADA showers?

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Michelle Rosenberger Partner, ArchEcology, LLC Mar 16 2014 LEEDuser Member 5447 Thumbs Up

Hi Lisa,
We generally set up a separate fixture group for the ADA showers and assign a default 5% of the FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. population to them.

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Michelle Robinson Re:Vision Architecture Mar 17 2014 LEEDuser Member 704 Thumbs Up

And if the shower stall can be switched between two flow rates, the LEED Reviewers will likely require you to assume worst-case scenario for water usage -- so assume they'll be using the higher flow rate all the time for these two shower stalls.

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E H Sustainability Architect Mar 17 2014 LEEDuser Member 3101 Thumbs Up

I would set up two fixture groups, one for the ADA shower & one for the regular shower. If the ADA showers are accessible to the whole building population, you should assign a percentage of the population to each shower fixture group based on the ratio of ADA showers to regular showers.

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Lisa Marshall Ecological Building Strategies Mar 17 2014 Guest 48 Thumbs Up

Thanks so much for your help with this, one final clarification. The plan is to create two user groups - 1)Non-ADA showers - use the base building user FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. count. 2) ADA shower stalls - Use the ADA user group at 5% of FTE at the higher gpm use. Correct? If this is the case, my only question would be that in most cases, non-ADA building users do tend to use the ADA showers and it would appear that this use would not be accounted for in the above strategy. (maybe this is ok??)

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Michelle Robinson Re:Vision Architecture Mar 17 2014 LEEDuser Member 704 Thumbs Up

I think it really depends -- in some buildings the ADA showers basically NEVER get used. In other buildings there is enough demand for showers that they may need to get used frequently. It also depends on what the difference is between the ADA showers and the standard showers and whether or not people will shy away from using them for that reason. Therefore it really depends on the specific installation.

What is the flow rate for the shower heads in the standard showers? If the standard showers have the lower flow rate it could look like you're gaming it.
The most conservative option assuming the ADA showers use more water than the standard showers would be to run it like E.H. suggested above with "a percentage of the population to each shower fixture group based on the ratio of ADA showers to regular showers."
However, depending on the design and how you think the showers will be used, Michelle Rosenberger's approach could be argued as well.

Oh, and the first User Group will be for less than 100% of the FTEs -- part of them will be assigned to the ADA user group. So it may end up with 95% FTEs in User Group 1 and 5% in User Group 2 or it could be 80% and 20% or whatever seems realistic in your situation.

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Jens Apel
Feb 21 2014
Guest
917 Thumbs Up

Daily uses public vs. private in hotel

I am working on a hotel NC certification. It is clear that the guests count as residents with 5 uses per day for toilets and faucets. But there is a public toilet block next to the breakfast room. Has anyone ever tried to split the 5 daily guest uses between hotel room and public toilet?
It is difficult to tell an exact number, but at least some of the guests will use the toilet at the breakfast room instead of their guest room toilet.
Any ideas?

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LEEDme STRATEGIE D'IMPRESA Feb 21 2014 LEEDuser Member 74 Thumbs Up

For a hotel (just NC certified) I used for guests 5 uses per day (residential use), for employers 3 uses (FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. use). Guests that will use the toilet at the breakfast room will not use their guest room toilet, the total uses amount is the same.

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Jens Apel Feb 24 2014 Guest 917 Thumbs Up

Yes, this would be my approach too. But as there may be urinals and autocontrol faucetsAutocontrol faucets have automatic fixture sensors or metering controls. in the public restroom it may be easier to save water here instead of e.g. with the guest room showers (comfort issue). But then the split of guest uses between hotel room and public restroom is important.
Does anyone have a standard approach or hints for splitting residential / hotel use in private and public?

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Michelle Robinson Re:Vision Architecture Feb 24 2014 LEEDuser Member 704 Thumbs Up

I don't know about a standard approach, but I think it would be less than half the hotel guests using the breakfast room toilet instead of their hotel room toilet for one use per day.

Keep in mind that the breakfast room toilet will be a public lavatory with a much lower max. flow rate and much lower overall water use compared to the showers. So you might want to run some calcs both ways to see if it's even worth pursuing this route (start with simply 4.5 uses in the hotel room and 0.5 uses in the breakfast room restroom, which would be more public restroom uses than would realistically be used) to see if it's even worth breaking it down to the public restroom. The 2.2 gpm residential lav faucet can easily be reduced to 1.5 gpm (or even 1.0 gpm with the right type of aerator), and the run time will be twice as long as the 0.5 gpm max flow rate for the public lav faucet. The total gallons of water for the public lav likely won't even really make a dent compared to the showers and other residential water usage...

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LEEDme STRATEGIE D'IMPRESA
Feb 14 2014
LEEDuser Member
74 Thumbs Up

temporized faucet

The water use reduction additional guidance says: the flow rate is determined using the flow rate in gallons per minute (gpm) and the duration setting (in seconds) for the metering faucet. When using metering sensor faucet or in default 12 second duration of flow representing the total of all run times during the hand washing process should be used.
If I have a temporized faucet (clicle 6sec duration - 2.5 Liters / clicle), which is the value to be inserted into the template?

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