Water-use reduction is a good opportunity for all projects to earn points. If you’re familiar with this credit from earlier versions of LEED, though, keep in mind that it’s gotten harder. LEED 2009 introduced WEp1: Water Use Reduction as a prerequisite, calling for a 20% reduction for all projects. In contrast with NC-v2.2 WEc3, which used to award one point for a 20% reduction, the points for 2009 now start with a 30% reduction with for two points, and go up to four points for a 40% reduction.
The baseline for measuring water savings 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.
Even with these more stringent requirements, both the credit and the prerequisite should still be fairly easy to achieve with careful fixture selection. You also have the option of replacing 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. with non-potable sources—for example using captured rainwater, or reusing lavatory water, to flush toilets.
Since you will already be designing fixtures to meet the 20% prerequisite, it is not much of a stretch to meet the 30% threshold to start earning points under this credit.
If you pay close attention to the flow rates of the water fixtures you select (gallons per minute for flow fixtures and gallons per flush for flush fixtures), you should be able to achieve a 30% reduction in water use by using widely available efficient fixtures—at a minimal cost premium and without compromising comfort.
Dual-flush options like Sloan's Uppercut dual-flush flushometer are a common way to help earn this credit. Image – Sloan Valve Co.Some typical approaches here include low-flow faucets with sensors, low-flush or dual-flush toilets, and low-flush or waterless urinals. Use 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. and rainwater for toilet flushing is also a fairly common way to contribute to the credit.
Combining several of these strategies can bring your water savings within the 30%–40% range, maxing out your points for this credit. A 45% reduction makes you eligible for an 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. point under IDc1.
Take note: both WEp1 and this credit address interior water use only, but certain strategies that apply to this credit—like graywater reuse—can also be applied to outdoor water use reduction. It is also important to understand that the prerequisite and credit only cover water closets, urinal, lavatory faucets, showers, kitchen sink faucets and pre-rinse spray valves. Other water using appliances and irrigation are not included.
When water-efficient fixtures first appeared in the 1990s, they often didn’t perform very well, creating a lot of doubts that still may be harbored by some project team members. Research and development as well as new testing protocols have really changed things since then, so make sure these doubts are put to rest. Providing hands-on experience with efficient fixtures by visiting another LEED building is a good way to do this.
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.
Include goals for water-use reduction in the Owner’s Project Requirements (OPR) for EAp1: Fundamental Commissioning. Reduced use of hot water with efficient fixtures can save a lot of energy.
Perform a water-balance study for the entire project to inform decisions about where to focus water-saving efforts. Understand which end uses require the most water, identify all alternative water sources available onsite—such as rainwater and graywater—and note opportunities for using that water for interior water use and/or irrigation.
Outdoor water use is not part of this credit. But looking at the whole system to understand how indoor water use compares to outdoor use can help you gauge where to focus reduction efforts for the greatest benefit. Some water-saving strategies can address both indoor and outdoor water needs holistically. For example, graywater collected from interior sink fixtures can be used for landscape irrigation, benefiting WEc1: Water Efficient Landscaping. However, this strategy will not contribute to a water reduction for this credit.
Appliance and process water uses such as clothes washers, dishwashers, cooling tower makeup, and others, need not be included in the LEED water use reduction calculations for this prerequisite and credit.
You can earn an Exemplary Performance point through IDc1 for a 45% reduction. To help you meet this threshold, you can include appliance and process water in the calculations, even though that’s not allowed for the standard credit calculations.
Core and Shell projects should consider the impact of fixtures that will be used by tenants. The ability of a LEED-CI project to earn this credit for itself could be either helped or harmed by choices made for the LEED-CS project.
Establish preliminary goals for water-use reduction. Consider setting water-reduction goals higher than the 40% reduction required by this credit, and aim for a reduction greater than 45% or higher for exemplary performance under IDc1. You are likely to need rainwater or graywater reuse to reach this threshold.
Up-front costs for a 30% reduction may be minimal, since project teams will already be integrating water-saving techniques for the 20% reduction prerequisite.
Target your efficiency efforts at fixtures that use the most water.
For residential projects, showers typically use more water than other fixtures due to the duration of use.
For commercial projects, toilets and urinals typically use more water than other fixture types.
When water-efficient fixtures first appeared in the 1990s, they often didn’t perform very well, creating a lot of doubts that still may be harbored by some project team members. Research and development as well as new testing protocols have really changed things since then, so make sure these doubts are put to rest. Providing hands-on experience with efficient fixtures by visiting another LEED building is a good way to do this. Providing information on testing results of products is another good way to sway hesitations (see GreenSpec’s related products in the right-hand column for more information).
Are composting toilets an option? While not common, composting toilets are waterless fixtures that go a long way toward achieving this credit. However, they do affect programming and layout, so consider them early in the planning stage.
Consider replacing potable water use with alternative sources such as collected graywater, rainwater, municipally supplied treated wastewater, or wastewater treated onsite for reuse.
Well and pond water are not considered “reused” 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 and rainwater collection systems can offer a potential non-potable water source for interior applications. However, you may find that it is easier—based on code issues and simplicity of system design—to direct reused water to an irrigation system or cooling tower. All solutions should be viewed in the context of finding the best whole-system approach for building and site water use.
Consider occupants when debating whether to use graywater or waterless and/or dual-flush fixtures. Cultural perceptions of these types of applications may need to be evaluated to gauge whether they will be successful in your building. It is also a good idea to have education outreach in order for building occupants to know how to use the new fixtures and to understand the importance of water reduction strategies.
Check local codes and restrictions. Throughout the U.S. there are widely varying laws addressing water use, and many states have very different approaches to rainwater collection and greywater/blackwater reuse.
Check for local incentives through municipalities and utilities that reward or encourage water-saving strategies—as well as restrictions that may apply. Rebates are common, as are plumbing codes restricting certain water-savings technologies such as waterless urinals, graywater reuse, onsite wastewater treatment and reuse, rainwater harvesting, composting toilets, and other strategies. See Resources for more.
Determine the number and types of occupants in the building. The water-use calculations are based on occupant use and the number of full-time equivalent (FTE) occupants, including employees and visitors—not the number of water fixtures.
The FTE occupancy number you use must be consistent with the FTE occupancy numbers used in all your other LEED credit submittals, including:
If the numbers of FTE occupants or transient visitors are not known by the Core and Shell project, you can use the default FTE numbers based on square footage shown here, from the LEED Reference Guide Appendix 1.
Determine user groups for the various water fixtures, as not all occupants may be using all fixtures. For example, employee restrooms and customer toilets in a retail store have different usage patterns that would affect the water use calculations if the fixtures were different. For example:
Run preliminary water use calculations to establish the baseline water use and confirm goals for water-use reduction. This should include clearly identifying target flow and flush rates for fixtures.
Like the prerequisite, this credit only includes core water uses—bathroom sinks, toilets, urinals, showers, kitchen faucets and prerinse 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.
The baseline for commercial lavatory faucets has been changed in LEED 2009 to 0.5 gpm, from 2.5 gpm in previous LEED rating systems. There are a handful of aerators and commercial faucets that perform better than 0.5 gpm, but the use of this low baseline means that you will probably need to focus on getting water reductions elsewhere.
Reductions in potable water used in flush fixtures can also contribute to the achievement of WEc2: Innovative Wastewater Technologies.
Select water-efficient fixtures and strategies. Gather information on applicable fixtures, including manufacturer, model number, and flush or flow rates.
Use the calculator built into the LEED Online credit form to help facilitate decision-making. Re-run comparisons between the baseline and design-case water budgets until the final selections of water fixtures and strategies have been made and the project’s water reduction goals are satisfied.
Design and 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 can 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, which is less common, can cause similar problems.
Piping to interior water fixtures is doubled when graywater or rainwater is reused in addition to potable water. This is likely to add upfront costs, but can potentially reduce water and sewer charges.
Sensors on toilets and faucets are sometimes 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 as they may interpret the flow of water as a solid object. If you do choose lavatory sensors, look for models with adjustable flow durations, and test the sensitivity of the sensor.
The LEED calculation estimates a standard 15-second use for faucets, so setting the flow duration to a shorter time of 10 seconds interval can help save water and contribute to earning the credit.
Flow restrictors and aerators can cost only a few dollars per fixture and can help add efficiency to more conventional sink fixtures. This can also be an easy inexpensive way to retrofit existing faucets; however, make sure restrictors or aerators are compatible with faucet fixtures.
Many commercial toilets can be retrofitted with dual-flush flushometers, which can cost less than installing new dual-flush toilets. Check with manufacturers for retrofit compatibility.
Toilet-lid-sink retrofits for standard toilets are one of the most basic and easy graywater reuse tools available, costing around $100. When toilets are flushed, potable water first flows though the sink for handwashing before filing up the toilet tank for flushing.
Specify efficient water fixtures in construction documents. Be sure to include specific flow and flush rates (gpm or gpf) for each type of fixture.
Specify signage for water fixtures or strategies that may require special instructions for use, or educate users on water savings. This may include signage for explaining proper operation of dual-flush toilets, waterless urinals, indicating non-potable water if supplied at faucets, and distinguishing pipes carrying reused water for operations and maintenance personnel.
If collecting rainwater or reusing graywater, ensure that the key system components, such as water treatment and cisterns, are not removed during value engineering.
Apply for any water-reduction incentives and rebates available through local municipal water authorities or utilities.
Fill out the LEED Online credit form and upload water fixture cut sheets to LEED Online.
The contractor should ensure that the correct fixtures have been purchased and that applicable water reuse systems or specified metering systems have been installed.
Make sure supply pipes carrying non-potable water are clearly color-coded and labeled to avoid inadvertent connection with potable water lines.
Provide building managers with manuals and guidance for all fixtures and fittings, water-reuse technologies, onsite water treatment systems and unconventional products.
Consider installing permanent water metering for ongoing monitoring of the project’s water use. A submetering 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, faucet sensors and other unconventional fixtures.
Excerpted from LEED 2009 for Core and Shell Development
To further increase water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems.
Employ strategies that in aggregate use less water than the water use baseline calculated for the building (not including irrigation). The minimum water savings percentage for each point threshold is as follows:
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 where available. Use high-efficiency fixtures (e.g., water closets and urinals) and dry fixtures, such as toilets attached to composting systems, to reduce the 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. demand. Consider using alternative on-site sources of water (e.g., rainwater, stormwater, and air conditioner condensate, 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 (e.g., toilet and urinal flushing custodial uses. The quality of any alternative source of water being used must be taken into consideration based on its application or use.
1. Table adapted from information developed and summarized by the U.S. Environmental Protection Agency (EPA) Office of Water based on requirements of the Energy Policy Act (EPAct) of 1992 and subsequent rulings by the Department of Energy, requirements of the EPAct of 2005, and the plumbing code requirements as stated in the 2006 editions of the Uniform Plumbing Code or International Plumbing Code pertaining to fixture performance.
This is a referenced standard for this credit.
WaterSense label helps US consumers choose high-quality, water-efficient products.
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.
A spreadsheet model that uses water/energy relationship assumptions to analyze the potential of water savings and associated energy savings.
A map with regional water information.
Search for local rebates for water efficiency products.
Searchable national database of toilet rebates.
This chapter addresses the following questions: What's the problem? What practices might be used to solve it? How effective are they? What do they cost? Where have they been used successfully? Practices for system users residential, industrial/commercial, and agricultural are presented first, followed by practices for system operators.
An advocate for water-efficient products and programs. Provides information and assistance on water conservation efforts.
Information and links to a range of water-related issues.
Offers web-based information exchange, workshops, and other educational opportunities.
Compilation 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. laws.
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 CS-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.
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.)
Similar to Diego's comment, we actually have two buildings where we are installing the plumbing infrastructure as part of the Core and Shell scope, but not the acxtual fixtures. Instead, We are mandating in the lease agreement the flow rates of each fixture (similar to lease mandating lighting levels that can not be exceeded on the energy side of things). I just want to make sure that this is acceptable. Our language is very specific, i.e. water closets can not exceed 1.28 gpf, sensor faucets at .35 gpm, urinals not to exceed .125 gpf, etc.
Jay, a lease agreement can and should be used to specify tenant fixture performance.
Is possible, for a LEED CS project to apply for the three cases (A, B y C), that are expressed in the appendix 4: Tenant Lease Agreement.
I.e. is possible to comply with each opcion by a tenant lease agreement, or only is possible to apply for one of those cases.
I will appreciate if you can help me as soon as possible.
Diego, it is possible to use all three cases for different credits. For example, you can use Case A for WEp1, and Case C for SSc4.2.
I have a question regarding project of office building in Prague( LEED 2009 CS).
I didnt find anywhere how to add into WE Cr.3 LEED ON-LINE Form the amount of rainwater used for flushing toilets. Any idea how to do that? Perhaps through special narrative?
Tomas, that is right—you need to do it as an alternative compliance path.
The Owner is constructing a tower with high end tenants on the his scope. He wants to leave to the tenant the installation of the water fixtures to give them freedon on the design according their tastes. The core and common spaces have not restrooms considered. My question is:
To comply with the Prerrequisite, perhaps I could have some restrictions and requirements on the lease agreement. But how would be possible to comply with this credit is I cannot foresee the potential savings? moreover, how can I use the synergies that this credit has with the WEc2? Is it possible to have compliance on these credits with these conditions?
Perhaps you could provide a list of approved fixtures (based on flush / flow rates) that meet the credit requirements? Therefore, tenants would have some options they can choose from but would they all would still fall within the water use reduction goals for the project.
I can not figure out how to calculate this for a core and shell office building that is 3/4 leased.
You could do some kind of survey of the tenants.
Sound tough? You're going to love this suggestion: check CS Appendix 1 in the LEED Reference Guide for default occupancy numbers!
Capturing rainwater for interior water use can reduce stormwater runoff quantity.
This prerequisite is the starting point for the credit. The same water-saving strategies apply to both places.
Water use reductions for toilets and urinals are calculated both in WEc3 and in WEc2, helping earn points in both places.
Water use reduction, particularly reduction in hot water use from showers and sinks, directly translates into energy savings.
Water-use metering and hot water metering are worth including in a measurement and verification plan.
Do you know which LEED credits have the most LEED Interpretations and addenda, and which have none? The Missing Manual does. Check here first to see where you need to update yourself, and share the link with your team.
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