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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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."
Not for individual fixtures. You only have to meet the LEED requirements for your fixtures as a group.
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.
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!
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.
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.
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.
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.
The FTE occupancy number you use here must be consistent with the FTE occupancy numbers used in all other LEED credits, including:
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.
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.
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.
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.
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.
Excerpted from LEED 2009 for New Construction and Major Renovations
To increase water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems.
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.
The following fixtures, fittings and appliances are outside the scope of the water use reduction calculation:
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.
Pages 62-69 of this legislation set federal standards for plumbing fixtures.
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.
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.
WATERGY is a spreadsheet model that uses water/energy relationship assumptions to analyze the potential of water savings and associated energy savings.
This website offers links to state and regional water information.
This site provides a number of studies related to water.
AWE advocates for water-efficient products and programs and provides information related to water conservation.
The Office of Water coordinates EPA's efforts to protect drinking water, oceans, watersheds and other aquatic ecosystems.
This organization promotes rainwater catchment in the U.S.
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.
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.)
Carefully research products and examine cut sheets to find fixtures and fittings meeting the credit requirements, as shown in these examples.
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."
Documentation for this credit can be part of a Design Phase submittal.
We received a reviewer comment saying since we had an adjustable shower head we would have to assume the highest gpm setting. We'd like to appeal the credit and ask that the gpm of the 3 shower head setting be averaged to determine the gpm as is done with the dual flush toilettes. It seems a bit rash to assume that everyone will re-adjust the shower head to the highest setting. It would be like assuming that everyone uses the higher flush option on the dual flush toilets.
Has anyone had any issues with adjustable shower heads?
In our shopping mall CS project the all water fixtures in tenant spaces are controlled by tenants (shops + restaurants) and the owner has no control over the fixtures. Water use is submetered and tenants pay according to usage. Are these fixtures within the CS scope?
The project is a residential building, but also has a small recreation space in cellar and a small retail space and gym on ground floor, how should the usage groups be defined? More specifically, if I am going to create a usage group for the resident apartments, then don't i also need to allocate some of that occupancy for the recreation spaces restrooms, etc.? This seems like such an amateur question, but does each fixture group value per each category (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., transient, etc.) need to equal the Daily Occupancy values defined in one of the PI forms?
We are working on an interior rennovation of a multi-level office building with one owner/tenant. We are not touching the core, shell or landscape. As the core is where the restrooms are located, can the project be exlcuded the restrooms from WEp1?
E H, the NC rating system covers the whole building scope. You cannot exclude fixtures not in the construction scope. You could do this for a CI project.
EH and Tristan - There was an addenda to address this issue for NC.
From the May 9, 2011 Addenda:
For additions to existing buildings, only the fixtures within the project scope must be counted for the prerequisite. To earn points under WE credit 3, all fixtures necessary to meet the needs of the addition occupants must be included, even if they are located within the existing building.
You are ok on the prerequisite but you can't get any points "all fixtures necessary to meet the needs of occupants using the addition must be included, including those located within the preexisting building." to get points under WEc3
The project is not an addition . . . So, I don't think it will qualify for the addenda. And, as the building has one owner/tenant with all floors interiors being renovated, I'm not sure it will fall under LEED CI . . .
Are the fixtures in a shared dormitory community bathroom considered residential or public? The bathrooms (including showers, toilets, and lavs) are for the residents/students, one per floor. Thanks.
Todd, this sounds like a residential application to me.
My project is planning to use Jacuzzi as one of the sanitary fitting in the master room.
I got a question about what is the baseline flow rate for Jacuzzi in calculation and which guideline should I refer to? Should I use the residential showerheads with 2.5 gpm as listed in LEED guideline?
is not regulated...does not go into WEp calcs...for energy modelling the baseline = proposed for water and equipment usages pertaining to it.
In a swimming pool facility it is very likely that almost all users do take a shower before leave. However, the default fixture use for showers defined in LEED implies that only about 10% of all users (converted in 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 take a shower. My question is if anyone has already faced some similar situation and can advise me on how to solve this issue.
Thanks in advance!
LOL! Perhaps it should be considered a 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. usage...As for the staff, the figure will fit, but for visitors, 10% is clearly wrong as you say. Ask USGBC how you should do this with the available LEEDonline system. I don't think it is possible.
Does anyone know if the inserts to reduce flow in faucets is recognized by the USGBC? The sink currently submitted to us comes stock with a 2.2 GPM aerator, but there are inserts available to knock it down to .5 GPM. Will the USGBC recognize the sink as .5 GPM with the insert, even though it is easily removable?
Thanks for the help,
Update: I have learned that they do count.
Mark, thanks for the update. Had I gotten to your question earlier that would have been my guess. In practice I think the less removable the better, but I haven't seen USGBC splitting hairs over this.
If we are installing low-flow faucets with vandal-proof aerators and sensors such that the water flow stops when a user's hands are not near the faucet, how should we account for that in the LEED template? Shouldn't we see savings from having elected to install the aerators and the sensors?
You will find the answer page 4 chapter "Public Metering/Autocontrol Lavatory Faucet – Gallons per Cycle Conversion" of the "Water Use Reduction Additional Guidance" quoted in the above LeedUser "bird's eye view". The link toward this doc in the above mentioned text is wrong. The correct link is http://www.usgbc.org/Docs/Archive/General/Docs6493.pdf
Thank you, Serge! Really appreciate your help.
We are running preliminary water calculations to verify that we meet the WEp1 requirements.
The project will have 2 usage groups, the homeless patrons and the staff. The homeless residents will have 2 bathrooms that they will use, which will include stainless steel penal fixtures, and the staff will have a separate bathroom they will use.
The homeless shelter will be open for the homeless from 3pm to 8am. At no time will anyone other than the staff be in the shelter between 8am and 3pm.
Our question is what designation do we need to consider the non-staff, would we count them as residents or an 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.?
I would expect the non-staff would be "residents" since I imagine they'll be showering there and everything as if that were their home.
I think you could make an argument for lower toilet uses, though, since there won't be any "residents" there for 7/24ths of the day (residents only present for less than 3/4 of the day but more than 2/3 of the day...) Of course in a "typical" residence, there's no one home for 8+ hours/day while they're off at work or at school... So perhaps there's no difference...
You could always run the calcs both ways (full "resident" usage vs. 3/4 resident usage). As long as you meet your water savings goal both ways, make a note on the LEED form as to what you assumed, why you assumed it, and that you ran the calcs the other way as well and what the water savings would be then. That would be your safest approach I think.
Our project is pursuing NC certification, but it includes a tenant portion which is uncontrolable by the owner. Fitness gym with shower facility is included in the tenant portion. It is difficult to force the tenant to use low flow shower.
Our questions are followings;
1. Is it OK to calculate water useage in the tenant area as neutral as the baseline, although the project is pursuing NC certification?
2. We have a problem in calculating shower useage at the fitness gym. Is it OK to use 0.1 times per a user per a day, which is the same as 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. occupant ? The transient occupants are assumed to use shower 0 times per a day.
Any comments would be appreciated. Thank you.
My office project has a "Wellness" room whcih includes a lav faucet & toilet. However, the intent of the space is for sick or injured (on the job) employees so on average (based on the companys use of the room in other facilities) the fixtures are used once or twice a week. How do i include them in the WEp1 calculations since they will not get the use of a typical fixture?
My thoughts were to create a separate fixture group but that requires a number of 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.'s to calculate daily useage.
Thanks in advance
This does sound like a separate fixture group scenario. I've done many for various purposes though not this particular issue. Yes, you will have to assign a percentage of users to these fixtures. You will have to extrapolate the company use in other facilities into a number of users/injuries rather than once or twice a week. And don't forget that if there is no urinal you will have to account for that differential by using a non-default calculation on the toilet use.
Michelle, thanks for the response and info. But I have more questions.
So I identify a number of users and uncheck default since it is a uni-sex bathroom. However, the daily uses is where I am stuck.
If I have 20 employees and througout the course of the year, lets say all 20 visit the wellness center once. So my number of users would be 20...but the daily use would be less than 1. And the template does not allow for me to use a number less than 1....what am I missing here?
Thanks again for the insight
Very tough scenario. And you are right you can't use less than one for either use or FTEs. I would suggest that you are not using the full FTE count with one use per year. Rather you are converting the total uses per year into a specific subset of users - the percentage who get sick or injured.
So you need a rationale you can explain like X occurrences/260 working days yields some percentage that you could multiply by your 20 FTEs. Then once you have a subset (likely 1) that you can explain. I would use 1 use only for lav and toilet indicating they are only there one time rather than typical.
You are going to take a hit but if your fixtures are low enough it might be tolerable. Here's hoping you have a 0.5 gpm metered lav. That's my best shot I'm afraid. You might check CIRs to see if there is another route given your scenario.
In some sense, it's expensive to install plumbing fixtures that no one really uses. It may be that these rooms are used more than you think for privacy or other reasons because they're there. Good luck.
In the form Table WEp1-2 Fixture Groups Definition, list these 20 employees as a separate fixture group, and indicate the Annual Days of Operation for this fixture group as 20 (with each flush/flow fixture used once daily). Include a narrative explaining your rationale.
That sounds a lot simpler. I had no idea you can manipulate ADO this way. I have always thought that referred to the facility operations. Good to know.
The Water Use Reduction - Additional Guidance document seems to indicate that although 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 for flush fixtures and/or flow fixtures (i.e. rainwater harvesting) can be counted in water reduction calculations, this use is limited to "Retail and Healthcare" projects, presumably under their relevant rating systems.
Can anyone confirm that an alternative compliance path including rainwater harvesting in water use calculations has been successfully used for WEp1 and WEc3 for typical projects under LEED NC 2009?
Many thanks in advance!
Why do you have that impression? We are pursuing this on a Core & Shell project currently, though it has not gone through review. I see nothing in the Guidance to suggest that limitation. I can say that we've been doing this for many years, long before Retail and Healthcare existed as rating systems, and this option has always been available.
I may be reading this entirely wrong, but under 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 Calculations the first paragraph ends "Retail and Healthcare projects may apply on-site non-potable water sources for fixtures and 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. use reduction" -- not sure if this is a restriction or simply an additional clarification to usage on NC 2009 projects.
Anyway, if you've had success in the past using rainwater in the water usage reduction calcs, that about answers my question!
Thanks -- apologies for the name confusion, there was some sign-up confusion within the office.
Ah, I believe they are just trying to say you can do it for those types of projects which involved 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. also. Good luck.
1) So we're going to appeal our failed prerequisit (after finding the limit of 12 seconds on metering faucets). We are planning to upload an invoice for a type of airrator (perlator) product which will reduce the flowrate together with letter of intent signed by the owner that the product will be installed. Do you think this will be enough?
Ofcourse the online form will be revised for the new rates.
2) It should be noted that not only is the industry standard, in germany, that flowrates are set at 6 l/min, but it is also required by local quality standard certification programs... the link to the most noteworthy QA program used here is:
It is interesting that the industry standard in Germany and that of the IPCInternational Plumbing Code are so far from each other regarding flowrates (or implied flowrates).
Jean, what is the nature of your question? If the product produces the required flow rate, then what would be the issue?
It would be better to actually install the product, of course, rather than just promise to do so.
Thanks Tristan. The parts should be arriving this week. I'll wait till they are installed and get a letter confirming the installation. This is my first appeal, so I'm not sure what kind of actions are acceptable to "remediate" a problem, i.e. the amount of proof required.
I am inquiring about the difference between private lavatory and public lavatory faucets. Based on the reference guide, I understand that all faucets in restrooms other than hotel guest rooms and hospital patient rooms are to be considered public lavatory faucets with a baseline flow rate of .5 gpm. If a .5 gpm flow rate is used as the baseline, how can the flow rate be improved at these faucets to contribute to the points? Please advise. Thank you!
We often use a metered faucet with a 0.5 gpm flowrate. That means using the calculation - 0.5 gpm X 12 sec duration / 60 seconds - you enter a proposed rate of 0.1 gpm. That can help considerably depending on your scenario.
We are using metering faucet for our project.
Its unclear what kind of pressure is considered when calculating the water consumption for 12s cycle. Can you please specify that?
We have come across an issue regarding flowrates and pressure.
LEED states 2.5 gallons per minute at 80 psi for showers for example.
Our manufacturer data sheet states 1.53 gallons per minute at 1.45 psi. When entering in the LEED form, should we just enter 1.53 or should make any calculations to ensure the pressures are the same?
Working on my 1st project that includes a pre-rinse spray faucet for a restaurant/cafe type setting. What should should be shown as the total daily uses and the duration on the template? We know the gpm.
The LEED Reference Guide for Green Building Design and Construction, 2009 Edition (Updated June 2010) 11/1/2011 Addenda clarifies that for projects with commercial pre‐rinse spray valves, there is no longer a baseline performance standard from which to claim savings; rather, the prerequisite requires only that the flow rate comply with the ASME A112.18.1 standard of 1.6 gpm or less.
Hej! We are integrating a water tank in our project to supply the toilets with rainwater and to supply landscaping with water. We go for 40% water reduction and we also go for 2 points under credit c1 water efficient landscaping (that means water use reduction of 50% for watering of plants).
When we calculate with the LEED tools, we need 78 m3 (20 605. 5 gal) water for landscaping in July. When we calculate the water need for flushing the toilets with LEED tools, we need 191.5 m3 pr month (2298.5 gal), this is provided we use 50% rainwater for flushing the toilet.
With the help of our landscaping architect and our HVAC engineer we though calculated that a 210 m3 (55 476 Gal) rainwater tank should be enough to supply both toilets and landscaping with water.
The question is, does the simultaneity factor for water for toilet flushing and landscape has to be 1 with respect to the size of the rain water tank (based on values calculated with LEED tools)? Or is there at all a connection between credit 1 and credit 3? In Denmark almost everyone is on holiday in July, so there will be only 10 to 20% employees in the building which would logically result in a much lower need for water for toilets during July. Can we take that into consideration? I could not find any documentation on how this issue is handled under LEED.
Thanks in advance!!
Interesting question. I think it is up to you to show that your system can meet the demands being placed on it. If there is a valid argument for sizing things in that way, even if on paper it won't meet peak demand for July, then you can make it.
However, some caution—assumptions about how a building will be operated such as when people will be on holiday are not always deemed relevant for LEED-NC, which is about how the building is designed, not the details of its operation.
To complicate things further, I am not sure without checking whether these forms are linked and whether this issue will even be apparent in a review of the LEED Online forms.
Should decorative fountains be documented under any water-related credits such as this one or the water-efficient landscaping credit?
No, decorative fountains would be excluded from the calculations. Include only the following fixtures and fixture fittings (as applicable to the project scope): water closets, urinals, lavatory faucets, showers, kitchen sink faucets and prerinse spray valves.
I have a LEED-NC 2009 hotel project and I am testing various fixtures in the WEp1 template. Although the LEED-NC reference guide says that for residential uses, both WCs and lavatories should be calculated at 5 uses/occupant/day, the several templates I tested (online and offline) use 0 uses per day as a default. This is frustrating, in that we cannot get any benefit out of our lower flow aerators, and nothing I do with the other fixtures can get the project to better than about 37.7% improved efficiency. If I manually put in the 5 uses/day/occupant with a 1.0 lav, we do great, but I don't know if there is a standard policy not to count this fixture.
Can anyone guide me on this?
I have had many instances when the default uses either don't calculate or mis-calculate. I beleive this happens when there is a mix of residential and commercial users. Despite the fixture group separations, the template still seems to struggle.
In those case, I have simply unchecked the default and manually entered the appropriate uses and uploaded the explanatory calc. 5 uses is correct for residential use for both fixtures. A 1.0 lav for hotel residents which is considered 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. is the appropriate baseline. Sounds like you are on the right track filling in the correct uses per day. Make sure you upload your explanation.
I'm working on a large commercial project where there are cookery demonstration rooms that up to 50 visitors will attend on a daily basis. These spaces have kitchen sinks and hand wash basins for demonstrators. Must these be included in the water use reduction calculations or can they 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. use?
We've done several projects with commercial kitchens both NC and CI. My understanding is that the kitchen sinks can be 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 excluded but the hand washing sinks are included. A designated hand washing sink is subject to the requirements no matter where it is.
That's a I thought, but good to have it confirmed.
I am working on LEED certification of hotel project. My question is regarding water closet use.I know that for residential, there is 5 uses/ day
But what is the number of low flush and full flush uses for hotel guests. Guidance talks about 1:2 ratio between full : low flushes, but I am not sure how this works for total o 5 uses.
Thanks in advance.
I assume you have a dual flush scenario with no urinals. We have encountered this also and didn't find any clear guidance. We have used 2 full and 3 half for both male and female. Considering the extensive Additional Water Reduction guidance document, it would be nice if this question could be specifically answered in the guidance or by LEEDuser in the facts above.
The Water Use Reduction Additional Guidance document states that residential projects must use a 1:2 ratio in terms of the number of full-flush to low-flush uses per day. Instead of using the typical 5 flush residential scenario, it’s essentially the same weighted average calculation as the commercial dual-flushA type of water-saving toilet that gives a choice of flushes depending on the type of waste solid or liquid. (without urinals). For example, if the dual-flush water closet is 1.6/0.8 gpf, the residential weighted average would be 1.07 gpf.
Our project is an office bldg with a Kitchen Restaurant in Europe.
We are looking for pre-rinse spray valves of 1.6gpm (6L/min) or lower available in France/Switzerland/Germany...
Has anyone found an American manufacturer that distributes here or an European one?
Charline, I can't say which if any of these distribute in Europe, but here is GreenSpec's list of pre-rinse spray valves that meet LEED requirements, plus a performance standard.
Hi! I went through descriptions how to calculate the design case for public metering/Autocontrol Lavatory Faucets and have among others the 2013 version "Water Use Reduction Additional Guideline" in front of me. The guideline states that baseline for public metering/Autocontrol Lavatory Faucets is 0.25 GPC and the design case is calculated by flow rate and 12 seconds duration. This is then benchmarked against 0.25 GPC. Example: design case= 1.32 GPM * 12/60= 0.26 GPC. Then I would benchmark 0.25 against 0.26 and find out that i actually use more water in the design case than the baseline. Is the calculation correct? Thanks.
Yes, the conversion is correct. Note that the lavatory fixture can exceed the baseline, as long as your overall performance of all applicable fixtures demonstrates a 20% reduction.
Our project includes toilets for disabled persons and I am not sure how to include this in our calculations.
The toilets for disabled will be used only by disabled users and nobody else will be permitted to use them. Therefore, I will have to predict number of disabled in the building based on national statistics (percentage from the FTEs and visitors).
Has anyone tried this approach or is there a better way to do that? I am sure that this issue must be quite common.
Thank you in advance!
Have you received any guidance with this? We have similar issue at our project.
We have tried this approach on a project where we determined the number of people who would use the toilets for diabled users as 2% of the total 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.. We have just submitted this and we are waiting to see if it will be accepted. Will keep you posted.
I apologize for the simplicity of my question, but I want to make sure I am providing accurate information.
If I have a commercial office building with 2 identical unisex bathrooms with no urinals, accessible to all tenants, I only have 1 fixture family for water closet, 1 fixture family for public lavatory faucet? I want to make sure that I don't need to put each toilet in the list. I know it doesn't change the percentage, but I don't want to incorrectly state the annual water consumption.
Hi Rick- Yes, you should group together fixtures that have the same usage rate and water consumption rate. Your percentage water savings and annual water consumption should be the same if they were separated or combined. Make sure you've created and assigned the Fixture Group(s) correctly.
The project has male and female restrooms with urinals in the male restrooms, as well as unisex restrooms without urinals in the basement and ground levels.
Initially, I had defined just one Fixture Usage Group for the entire office since in theory all occupants will have access to all bathroom facilities. However, we received a comment saying we need to adjust the Total Daily Uses because the current scenario assumes that 100% of male occupants will use restroom that contain urinals, and the unisex bathrooms do not.
Should we define an additional Fixture Usage Group for the unisex bathrooms? But how do we decide how many people will use them?
Give us more details here, what is the type of the project and why you decided to put 3 three types of restrooms(male, female, unisex) to serve who? then this will lead you and us to determine the right daily uses.
You will need to make a reasonable assumption regarding male occupants that will utilize the restrooms without urinals. One approach is to determine the percentage of all males without access to urinals by calculating the total number of male restrooms with urinals vs. without urinals. Adjust your Total Daily Uses for the water closet and urinal fixture uses accordingly. In any case, I would provide a brief narrative explanation with your final documentation.
Hello Carlie, I have finised my documentation for WEp1 but I am not sure if I calculated correctly the number of people who use unisex restrooms and total daily uses of those toilets. May I contact you directly and ask for comments?
Hi Regina and Carlie--
I recently received the same comment regarding unisex bathrooms. I didn't separate them into a fixture group as the unisex bathrooms are spread throughout the facility-- anyone can access them and often a unisex bathroom is between a male restroom and a female restroom.
Here is my comment: "Unisex restrooms have not been accounted for in the calculations. If a percentage of male occupants will not have access to or will be expected to use restrooms without urinals, the default Total Daily Uses for water closets and urinals must be adjusted. Please provide a narrative and/or supporting calculations to explain the anticipated urinal usage."
I don't believe I should adjust Total Daily Uses for unisex bathrooms. However, since this is a prereq-- I am willing. I just don't know how to back out the uses for this.
Any advice will be appreciated.
I assume an ablution fixture used to wash before entering a prayer room would have to be considered in the water use calculations. What would the baseline rate of the fixture be? The same as a public lavatory?
Well, Following efficient practices is always a great idea in general but still i think its not covered under the scope here.
i may argue that it may fall under 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. category which also includes (Mop sinks, janitor sinks, swimming pools, bidets, and safety showers) because it doesn't have similar usage pattern as a public lavatory (water runs for longer periods).
But a second opinion would be good here.
Public and private lavatory faucets encompass all sinks used primarily for hand-washing regardless of location (February 2, 2011 Addenda); so if the ablution fixture described above is used primarily for hand washing then it would need to be included.
Tips and screenshots on LEED Online documentation.
Capturing rainwater for interior use can contribute to WEp1 as well as reducing stormwater quantity.
Capturing rainwater for interior use can contribute to WEp1 as well as reducing stormwater quantity, which can help with improving stormwater quality.
Graywater may be used for landscaping in addition to using it for indoor fixtures.
Reducing water use by toilets and urinals can help earn points in both WEp1 and WEc3, as well as in WEc2.
As water is saved in lavatory faucets, kitchen sinks and showers, you’ll need less hot water, saving energy.
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