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LEED v2009
Commercial Interiors
Water Efficiency
Water Use Reduction

LEED CREDIT

CI-2009 WEc1: Water Use Reduction 6-11 points

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Carlie Bullock-Jones

LEED Fellow, WELL AP

Ecoworks Studio
Principal

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Requirements

Employ strategies that in aggregate use less water than the water use baseline calculated for the tenant spaces (not including irrigation). The minimum water savings percentage for each point threshold is as follows:

Percentage Reduction

Points

30%

6

35%

8

40%

11

Calculate the baseline according to the commercial and/or residential baselines outlined below. Calculations are based on estimated occupant usage and must include only the following fixtures and fixture fittings necessary to meet the needs of the occupants including fixtures and fixture fittings that may be outside the tenant space: water closets, urinals, lavatory faucets, showers, kitchen sink faucets and pre-rinse spray valves. [Europe ACP: Water Use Baseline]

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: 13.5 lpf

Commercial urinals

1.0 (gpf)

4.0 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

Commercial prerinse spray valves
(for food service applications)

Flow rate ≤ 1.6 (gpm)
(no pressure specified; no performance requirement)

Flow rate ≤ 6 lpm (no pressure specified; no performance requirement)

Residential Fixtures, Fittings, and Appliances

Current Baseline (Imperial Units)

Current Baseline (Metric Units)

Residential toilets

1.6 (gpf)***

6 liters per flush (lpf)

Residential lavatory (bathroom) faucets

2.2 (gpm) at 60 psi

8.5 lpm at 4 bar (58 psi)

Residential kitchen faucet

Residential showerheads

2.5 (gpm) at 80 (psi) per shower stall****

9.5 lpm  at 5.5 bar (80 psi) per shower stall

 

*       EPAct 1992 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/9.5 lpm) 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 water 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

Alternative Compliance Paths (ACPs)

Europe ACP: Water Use Baseline
Projects in Europe may use the values defined by European Standards. [view:embed_resource=page_1=4887984] See all forum discussions about this credit »

What does it cost?

Cost estimates for this credit

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Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.

This information is also available in a full PDF download in The Cost of LEED v4 report.

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Addenda

1/27/2017Updated: 1/27/2017
Form Update
Description of change:
corrected ice machine baseline numbers for retail on process water and instructions tabs (v07)
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the fourth row of the table in the "EPA WaterSense Standards" column, replace "1.5 - 2.0^b" with "2.0^b"
Campus Applicable
No
Internationally Applicable:
No
10/1/2012Updated: 2/14/2015
Global ACP
Description of change:
Add "Imperial Units" after "Current Baseline" in the second column
Campus Applicable
No
Internationally Applicable:
Yes
4/1/2013Updated: 2/14/2015
Rating System Correction
Description of change:
Autocontrol faucet baseline Addenda (all rating systems). In the 2/2/2011 Addenda, replace the baseline in the related note below table with “Default duration for the metering type / autocontrol lavatory faucet is 0.25 gallons per cycle (gpc) for the baseline case and 12 seconds for the design case.”
Campus Applicable
No
Internationally Applicable:
Yes
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Remove the following text:U.S. EPA, Water Use Efficiency Programhttp://www.epa.gov/owm/water-efficiencyThis website provides an overview of EPA\'s Water Use EfficiencyProgram and information about using water more efficiently.
Campus Applicable
No
Internationally Applicable:
No
11/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the first line of the first paragraph, replace the word "buildings" with "tenant space" so the text becomes "...calculated for the tenant space (not..."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Rating System Correction
Description of change:
Replace the second paragraph with the following:Calculate the baseline according to the commercial and/or residentialbaselines outlined below.? Calculations are based on estimatedoccupant usage and must include only the following fixtures and fixturefittings located within the tenant space: water closets, urinals, lavatoryfaucets, showers, kitchen sink faucets and prerinse spray valves.?
Campus Applicable
No
Internationally Applicable:
No
11/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the first line of the first paragraph, replace the word "building" with "tenant space" so the text becomes "...for the tenant spaces (not..."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the first line of the sixth paragraph, replace "conservation" with "efficiency"
Campus Applicable
No
Internationally Applicable:
No
10/1/2012Updated: 2/14/2015
Global ACP
Description of change:
Add "Imperial Units" after "Current Baseline" in the second column
Campus Applicable
No
Internationally Applicable:
Yes
2/2/2011Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the section text with the following:The "Kitchen sinks" category encompasses 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. However professional grade / commercial faucets such as those used in a commercial kitchen would not be included. The "Public lavatory faucets" and "Private lavatory faucets" categories encompass all sinks used primarily for hand-washing regardless of location. Faucets whose usage patterns and flow rates are regulated for medical or industrial purposes (e.g. laboratory sinks) and do not fall under the definition of private or public use are not included. Faucets used exclusively for filling operations (e.g. pot-filler) can be excluded. All other fixtures and fixtures fittings must be included in the calculations unless there are special circumstances that justify excluding them.
Campus Applicable
No
Internationally Applicable:
No
4/14/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the third line of the fifth paragraph, replace the text "WE Credit 3" with "WE Credit 1."
Campus Applicable
No
Internationally Applicable:
No
11/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
In the paragraph, replace the word "buildings" with "tenant space" so the text becomes "...within the tenant space to reduce..."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the resource "Rocky Mountain Institute, Water," replace the text below the resource header with the following:http://www.rmi.org/rmi/pid172This portion of RMI\'s website is devoted to water resource efficiency.
Campus Applicable
No
Internationally Applicable:
No
10/1/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a third column to the table, reading as follows: Current Baseline (Metric Units) 6 liters per flush (lpf) 8.5 lpm at 4 bar (58 psi) 9.5 lpm at 5.5 bar (80 psi) per shower stall
Campus Applicable
No
Internationally Applicable:
Yes
5/9/2011Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the sixth row ("Lavatory Faucet") row of the table in the 11/2/2009 addenda, replace the related note below table with "Default duration for the metering type / autocontrol faucet is 15 seconds for the baseline and 12 seconds for the design case." This addenda is related to Addenda ID # 100000051.
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the first sentence with "Private or private 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."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Below footnote 1, insert the following:?Projects where fixtures or fixture fittings are not within the tenant spaceare exempt from WE Prerequisite 1.
Campus Applicable
No
Internationally Applicable:
No
7/1/2014Updated: 2/14/2015
Form Update
Description of change:
Corrected errors from previous version, including incorrect uses per day calculation. Added override functions for special circumstances. Modified built-in dual flush calculator. Added functionality for custom naming of tabs. Streamlined output fields. Added content for BD+C, ID+C, and Retail/Healthcare project types.
Campus Applicable
Yes
Internationally Applicable:
Yes
11/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
In the first line of the first paragraph, replace the word "building" with "tenant space" so the text becomes "...for the tenant spaces (not..."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the second paragraph beginning with "Calculate the baseline" with the following:Calculate the baseline according to the commercial and/or residentialbaselines outlined below.? Calculations are based on estimatedoccupant usage and must include only the following fixtures and fixturefittings necessary to meet the needs of the occupants including fixturesand fixture fittings that may be outside the tenant space: water closets,urinals, lavatory faucets, showers, kitchen sink faucets and pre-rinsespray valves.
Campus Applicable
No
Internationally Applicable:
No
10/1/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a third column to the table, reading as follows: Current Baseline (Metric Units) 6 liters per flush (lpf) 8.5 lpm at 4 bar (58 psi) 9.5 lpm at 5.5 bar (80 psi) per shower stall
Campus Applicable
No
Internationally Applicable:
Yes
4/1/2013Updated: 2/14/2015
Reference Guide Correction
Description of change:
"At the end of the section, insert the following text as a new paragraph:
""For hospitality projects, FTE 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 hotel Total Hotel Guests = 123*1.5 * 60% Total Hotel Guests = 111"""
Campus Applicable
No
Internationally Applicable:
Yes
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the seventh row of the table in the "Flow Fixture" column, replace "Low-flow shower" with "WaterSense shower"
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In footnote "b," replace "2.0 gmp" with "2.0 gpm"
Campus Applicable
No
Internationally Applicable:
No
10/1/2012Updated: 2/14/2015
Global ACP
Description of change:
Add "Imperial Units" after "Current Baseline" in the second column
Campus Applicable
No
Internationally Applicable:
Yes
11/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
In the first line of the paragraph, replace the word "buildings" with "tenant space" so the text becomes "...efficiency within tenant spaces to reduce..."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the resource "Water Closet Performance Testing," with the following:Water Studieshttp://www.ebmud.com/resource-center/publications/studiesThe site provides a variety of studies related to water.
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the second paragraph with the following:Calculate the baseline according to the commercial and/or residentialbaselines outlined below.? Calculations are based on estimatedoccupant usage and must include only the following fixtures and fixturefittings located within the tenant space: water closets, urinals, lavatoryfaucets, showers, kitchen sink faucets and prerinse spray valves.?
Campus Applicable
No
Internationally Applicable:
No
10/1/2014Updated: 2/14/2015
Reference Guide Correction
Description of change:
Private or private use applies to plumbing fixtures in residences, apartments, and dormitories; private (non-public) bathrooms in transient lodging facilities (hotels and motels); and private bathrooms [and patient rooms] within hospitals and nursing facilities.

Add the following to eligible fixtures section:

"For healthcare projects, fixtures used for clinical use related to medical procedures, such as surgical scrub sinks and exam rooms sinks, in hospitals and medical office buildings are excluded from the water use calculations. Medication room sinks, utility room sinks, and other exam/procedure/observation room sinks for clinical use are also excluded. Should exam/procedure/observation room sinks be used primarily for hand-washing, they may be included in the water use calculations at the project team’s discretion under the public lavatory category. If included, project teams should provide a narrative explaining the usage assumptions for these sinks.

Lavatories in hospital inpatient bathrooms and inpatient rooms are considered private. The inpatient lavatory and water closet should use the default residential usage assumptions (of five times per day per residential occupant), unless specific project conditions warrant an alternative. Lavatories in hospital inpatient rooms (outside the bathrooms) are considered private if used by patients and/or staff similarly to a residential lavatory, or can be exempt if they are used by staff primarily for medical or clinical use.

Nutrition station (pantry) sinks and hospital staff lounge sinks should be included in the water use calculations under the kitchen sink category."
Campus Applicable
No
Internationally Applicable:
Yes
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the second line of the first paragraph, remove "and subtracting any nonpotable water supply"
Campus Applicable
No
Internationally Applicable:
No
11/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the eighth row of the table in the "Fixture" column, remove the text "and janitor" so it becomes "Kitchen sink faucets"
Campus Applicable
No
Internationally Applicable:
No
10/1/2012Updated: 2/14/2015
Global ACP
Description of change:
Add "Imperial Units" after "Current Baseline" in the second column
Campus Applicable
No
Internationally Applicable:
Yes
2/2/2011Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the sixth row ("Lavatory Faucet") row of the table in the 11/2/2009 addenda, replace the duration (sec) of 15 with 30
Campus Applicable
No
Internationally Applicable:
No
11/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the paragraph, replace the word "buildings" with "tenant space" so the text becomes "...within the tenant space to reduce..."
Campus Applicable
No
Internationally Applicable:
No
11/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
In the first line of the first paragraph, replace the word "buildings" with "tenant space" so the text becomes "...calculated for the tenant space (not..."
Campus Applicable
No
Internationally Applicable:
No
1/8/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Insert the term "Tenant space" in alphabetical order with the accompanying text "Tenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the first, second, third, and fourth paragraphs with new text as indicated in the supplemental documentation.
Campus Applicable
No
Internationally Applicable:
No
10/1/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a third column to the table, reading as follows: Current Baseline (Metric Units) 6 liters per flush (lpf) Except blow-out fixtures: 13.5 lpf 4.0 lpf 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 Flow rate = 6 lpm (no pressure specified; no performance requirement)
Campus Applicable
No
Internationally Applicable:
Yes
5/9/2011Updated: 2/14/2015
Reference Guide Correction
Description of change:
Remove the paragraph beginning with, "Although water-efficient dishwashers..."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Remove both instances of "potable" in the section
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Rating System Correction
Description of change:
Below footnote 1, insert the following:?Projects where fixtures or fixture fittings are not within the tenant spaceare exempt from WE Prerequisite 1.
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Remove the following text:Fine Homebuilding Choosing a Toilethttp://www.taunton.com/finehomebuilding/pages/h00042.aspThis article includes several varieties of water-efficient toilets.
Campus Applicable
No
Internationally Applicable:
No
10/1/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a third column to the table, reading as follows: Current Baseline (Metric Units) 6 liters per flush (lpf) Except blow-out fixtures: 13.5 lpf 4.0 lpf 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 Flow rate = 6 lpm (no pressure specified; no performance requirement)
Campus Applicable
No
Internationally Applicable:
Yes
4/1/2012Updated: 2/14/2015
Reference Guide Correction
Description of change:
In alphabetical order, add the following definition for autocontrol faucets, "Autocontrol faucets have automatic fixture sensors or metering controls."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the seventh row of the table in the "Flow Rate" column, replace "1.8 gpm" with "? 2.0 gpm"
Campus Applicable
No
Internationally Applicable:
No
11/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the table with two tables as indicated in the supplemental documentation. (Note that this table was updated again on February 2, 2011)
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Rating System Correction
Description of change:
Replace the second paragraph beginning with "Calculate the baseline" with the following:Calculate the baseline according to the commercial and/or residentialbaselines outlined below.? Calculations are based on estimatedoccupant usage and must include only the following fixtures and fixturefittings necessary to meet the needs of the occupants including fixturesand fixture fittings that may be outside the tenant space: water closets,urinals, lavatory faucets, showers, kitchen sink faucets and pre-rinsespray valves.
Campus Applicable
No
Internationally Applicable:
No
11/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the first line of the paragraph, replace the word "buildings" with "tenant space" so the text becomes "...efficiency within tenant spaces to reduce..."
Campus Applicable
No
Internationally Applicable:
No
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In alphabetical order, insert the following text:Alliance for Water Efficiencyhttp://www.allianceforwaterefficiency.org/The Alliance for Water Efficiency provides information and assistance onwater conservation efforts.
Campus Applicable
No
Internationally Applicable:
No
4/1/2013Updated: 2/14/2015
Reference Guide Correction
Description of change:
"Below the first paragraph, enter the following text as a new paragraph:
""For hospitality projects, commercial kitchen sinks and bar sinks including pot sinks, prep sinks, wash down, and cleaning sinks are considered process water and are not included in the water use calculations. Hand washing sinks located in commercial kitchen areas that do not pass through a grease interceptor should be included in the water use calculations under the kitchen sink category."""
Campus Applicable
No
Internationally Applicable:
Yes
7/19/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the fifth row of the table in the column "Flow rate," replace "1.8gpm" with ""? 2.2 gpm"
Campus Applicable
No
Internationally Applicable:
No
5/9/2011
LEED Interpretation
Inquiry:

The installation of bedside patient care units, which is a combined toilet and lavatory, is required for some patient rooms. Can the patient care unit be excluded from the calculations since there are no low-flow options available?

Ruling:

All fixtures that are covered by the EPAct 1992 must be included in the credit calculations, even if there are no low-flow options available. The use of these fixtures by only the patients in a limited area can be factored into the calculations.

Campus Applicable
No
Internationally Applicable:
No
5/9/2011
LEED Interpretation
Inquiry:

Can untreated groundwater, unsuitable for drinking, contribute towards WE credits 1, 2, and 3 as a non-potable water source for irrigation and sewage conveyance?

Ruling:

This approach does not meet the intent of the WE credits. Although the local groundwater may not be suitable for drinking straight out of the ground, it still represents an important source of potable water. Applicable internationally.

Campus Applicable
No
Internationally Applicable:
Yes
10/10/2006
LEED Interpretation
Inquiry:

We are seeking clarification on the use of municipally provided non-potable water for achieving WEc3 under the LEED NC version 2.2 rating system. Use of municipally supplied non-potable water meets the intent of limiting or eliminating the use of potable water and reduces the burden on municipal water supplies. However, currently, the Reference Guide does not give clear direction with concern to WEc1, WEc2 & WEc3 and municipally supplied water: WEc1 states that water savings can be claimed through the use of "water treated and conveyed by a public agency specifically for non-potable uses." WEc2 states that water savings can be claimed through the use of "municipally treated wastewater." WEc3, however, makes no statements as to whether municipally supplied recycled water can count towards water saving calculations. However, the synergies between WEc2 and WEc3 calculations leads one to conclude that municipally supplied wastewater can be used for both credit calculations. Our project will be using municipally supplied non-potable reclaimed water for both irrigation and sewage conveyance (toilet flushing). Can you please clarify whether municipally supplied reclaimed water can be used to achieve both WEc3.1 and WEc3.2?

Ruling:

Update October 20, 2016: See the updated “Water Use Reduction Additional Guidance” document for new guidance on applying seawater or municipal wastewater to v2009 Water Efficiency credits.

Original ruling October 10, 2006
Municipally reclaimed water is not applicable to WEc3 achievement. This credit focuses on fixture efficiency and on-site water reuse. Applicable Internationally.

Campus Applicable
No
Internationally Applicable:
Yes
11/1/2011
LEED Interpretation
Inquiry:

Can reverse osmosis reject water be used as an innovative wastewater source? Reverse osmosis water is often used in lab, hospital and other process water settings.

Ruling:

Yes, on-site reverse osmosis reject water is an acceptable non-potable water source. Applicable internationally.

Campus Applicable
No
Internationally Applicable:
Yes
11/1/2011
LEED Interpretation
Inquiry:

This is an inquiry about the calculation of the FTE in relation to our project in Zurich, Switzerland. In the LEED Reference Guide on page 53 the calculation of the FTE is based on a 8-hour working day. That means that an 8-hour occupant has an FTE value of 1.0. The standard working day in Switzerland contains 8.5 hours of work.In a FTE calculation on the basis that is provided in the LEED Reference Guide the normal working day of one single person would have the FTE value of 1.0625. As a consequence of the, in case of 1000 people fulltime staff this FTE calculation would have additional number of 63 FTE in comparion to an FTE value of 1.0.Is it possible to calculate the FTE value for this project with an 8.5 instead of 8 hour day, so that we would have the FTE value of 1.0 for a standard 8.5 hour-working day?

Ruling:

The project team has inquired if projects in Switzerland may use 8.5-hours as their working day instead of 8-hours as in the US. Each full-time employee based on Swiss and US labor laws works an 8.5-hour day, which includes a half-hour unpaid lunch break and two 15-minute paid breaks. In order to maintain the baseline for projects everywhere when calculating FTE occupancy, all Swiss projects, including those industries that have an overtime work culture for full-time employees, should still use the 8.0-hour work day in their FTE calculations. Applicable internationally.

Campus Applicable
No
Internationally Applicable:
Yes
8/27/2004
LEED Interpretation
Inquiry:

Summary: Interpretation ruling pertaining to establishing the calculation baseline for Water Reduction Credits 3.1 & 3.2 when on-site tests have been conducted, and demonstrate that the supply water pressure levels (psi) to the fixtures are substantially below the 80 psi referenced within the Energy Policy Act of 1992. Context: The scope of the project incorporates new construction of four residential halls on a college campus, which house more than 250 students and staff. Three of the buildings are three stories, and the other is four stories. Description: The residence halls are incorporating a range of fixtures that are below the flow rates within the Energy Policy Act of 1992 (dual flush toilets, and faucets within the kitchens, kitchenettes, bathrooms & apartments). The showers in the residence hall are the largest water consumer (by a large %) within the residence hall buildings. To begin to understand the water amount actually used on the project, the owner conducted some initial on-site tests to determine the supply pressure to the plumbing fixtures, and how that translated into the actual flow. On-site tests for one of the buildings have been conducted on the flow rates of the shower heads with the following results: Fixture type currently installed = 2.5 gpm 1st floor: 52 psi static, 2.10 gpm 2nd floor: 46 psi static, 1.92 gpm 3rd floor: 41 psi static, 1.79 gpm 4th floor: 37 psi static, 1.85 gpm Question: o Would the design case account for the lower psi (reduced water use) by multiplying the \'Water Use\' column within the calculation template by the percentage of supply/baseline? For example for a shower on the first floor the \'Water Use" would be multiplied by 65% (52/80) or by just including 2.10 gpm as the flow rate for the fixture on this floor? o What is the appropriate methodology for establishing the calculation baseline when the water pressure supply rate (psi) is substantially lower than the 80 psi outlined as the baseline flow rates under the Energy Policy Act of 1992?

Ruling:

[Note: this ruling was revised on 9/1/04.] The underlying assumptions used for calculating projected water use savings should remain consistent between the baseline and design case. Supply water pressure varies across the United States and within individual buildings (as you note in your inquiry). Flow rates at 80 psi are used for the calculations in this credit for consistency and to reward use of efficient fixtures. It is recommended that all projects use the flow rates reported by the manufacturer at 80 psi for comparison with the Energy Policy Act of 1992 flow rates. If you wish to use on-site tests to report the most accurate volume of water use, you must be consistent throughout all fixtures and test both baseline and design fixtures. It is not acceptable to use flow rates at 80 psi for some fixtures and actual flow rates for other fixtures. Measurement can also be used to account for the benefits of whole-building strategies, e.g., flow restrictors at the water service entrance. Applicable Internationally.

Campus Applicable
No
Internationally Applicable:
Yes
5/9/2011
LEED Interpretation
Inquiry:

Are swimming pools excluded from the calculations for WE Prerequisite 1?

Ruling:

This is correct as the prerequisite only covers fixtures specified in the Reference Guide and regulated by one of the standards listed. These fixtures and fixture fittings include water closets, urinals, lavatory faucets, showers, kitchen sink facets, and pre-rinse spray valves. Applicable internationally.

Campus Applicable
No
Internationally Applicable:
Yes
7/1/2012
LEED Interpretation
Inquiry:

Can municipally supplied treated seawater for toilet flushing be used as a strategy for earning WEp1 and WEc1 Water Use Reduction?

Ruling:

Update October 20, 2016: See the updated “Water Use Reduction Additional Guidance” document for new guidance on applying seawater or municipal wastewater to v2009 Water Efficiency credits.

Update October 1, 2013
Note that LEED Interpretation 10117 has been updated to clarify that seawater must be treated to appropriate levels for non-potable uses in order to apply to WEc2 Innovative Wastewater Technologies; seawater that is treated to potable drinking water standards would not apply. Any on-site energy use to desalinate the seawater must be included in the EAp2/c1 calculations. Refer to the guidance document. Applicability of Seawater in Water Efficiency credits also updated.

Original ruling July 1, 2012
No, municipally supplied sources of non-potable water, including seawater, are not applicable to the WE fixture water use reduction credits, including WEp1 (D+C, EBOM) and WEc1 (CI) Water Use Reduction, or considered graywater. As stated in LI 1551 (12/12/2006) This credit focuses on fixture efficiency and on-site water reuse. In addition, the Water Use Reduction Additional Guidance document (updated 8/16/2010, http://www.usgbc.org/ShowFile.aspx?DocumentID=6493), confirms that the focus of the pre-requisite is water efficiency of the installed fixtures, regardless of the water source, and only on-site water reuse is available as an alternative compliance path.
However, municipally treated wastewater (including treated seawater) applies to SSc1 - Path 9 Innovative Wastewater Technologies (CI), WEc2, Innovative Wastewater Technologies (BD+C), and can be used if the two conditions of LEED Interpretation 10117 are met: 1) the seawater is municipally supplied or explicitly approved by the municipality and 2) meets all applicable codes and permitting requirements, so as not to contaminate the municipal wastewater system with high salinity. For EBOM projects, where no wastewater credit is available, the project may apply for innovation credit for use of this strategy."

----------
10/1/13 notes: revise ruling and update resource: http://www.usgbc.org/resources/seawater-guidance

No, municipally supplied sources of non-potable water, including seawater, are not applicable to the WE fixture water use reduction credits, including WEp1 (D+C, EBOM) and WEc1 (CI) Water Use Reduction, or considered graywater. As stated in LI 1551 (12/12/2006) This credit focuses on fixture efficiency and on-site water reuse. In addition, the Water Use Reduction Additional Guidance document (updated 8/16/2010, http://www.usgbc.org/ShowFile.aspx?DocumentID=6493), confirms that the focus of the prerequisite is water efficiency of the installed fixtures, regardless of the water source, and only on-site water reuse is available as an alternative compliance path.

However, municipally treated wastewater (including treated seawater) applies to SSc1 - Path 9 Innovative Wastewater Technologies (CI), WEc2, Innovative Wastewater Technologies (BD+C), and can be used if the two conditions of LEED Interpretation 10117 are met: 1) the seawater is municipally supplied or explicitly approved by the municipality and 2) meets all applicable codes and permitting requirements, so as not to contaminate the municipal wastewater system with high salinity. For EBOM projects, where no wastewater credit is available, the project may apply for innovation credit for use of this strategy.

**Update October 1, 2013: Note that LEED Interpretation 10117 has been updated to clarify that seawater must be treated to appropriate levels for non-potable uses in order to apply to WEc2 Innovative Wastewater Technologies; seawater that is treated to potable drinking water standards would not apply. Any on-site energy use to desalinate the seawater must be included in the EAp2/c1 calculations. Refer to the guidance document. Applicability of Seawater in Water Efficiency credits also updated

Campus Applicable
No
Internationally Applicable:
No
5/9/2011
LEED Interpretation
Inquiry:

Can children\'s toilets be exempt from the prerequisite because there are no low-flow options available?

Ruling:

There are children\'s toilets available that are 1.6 gpf. The project team must decide what is best for the clientele, but baby toilets cannot be exempt from the credit. Applicable internationally.

Campus Applicable
No
Internationally Applicable:
Yes
7/1/2012
LEED Interpretation
Inquiry:

Can municipally supplied treated seawater for toilet flushing be used as a strategy for earning WEp1 and WEc1 Water Use Reduction?

Ruling:

Update October 20, 2016: See the updated “Water Use Reduction Additional Guidance” document for new guidance on applying seawater or municipal wastewater to v2009 Water Efficiency credits.

Update October 1, 2013
Note that LEED Interpretation 10117 has been updated to clarify that seawater must be treated to appropriate levels for non-potable uses in order to apply to WEc2 Innovative Wastewater Technologies; seawater that is treated to potable drinking water standards would not apply. Any on-site energy use to desalinate the seawater must be included in the EAp2/c1 calculations. Refer to the guidance document. Applicability of Seawater in Water Efficiency credits also updated.

10/1/13 notes: link resource and edit ruling: http://www.usgbc.org/resources/seawater-guidance

No, municipally supplied sources of non-potable water, including seawater, are not applicable to the WE fixture water use reduction credits, including WEp1 (D+C, EBOM) and WEc1 (CI) Water Use Reduction, or considered graywater. As stated in LI 1551 (12/12/2006) This credit focuses on fixture efficiency and on-site water reuse. In addition, the Water Use Reduction Additional Guidance document (updated 8/16/2010, http://www.usgbc.org/ShowFile.aspx?DocumentID=6493), confirms that the focus of the prerequisite is water efficiency of the installed fixtures, regardless of the water source, and only on-site water reuse is available as an alternative compliance path.

However, municipally treated wastewater (including treated seawater) applies to SSc1 - Path 9 Innovative Wastewater Technologies (CI), WEc2, Innovative Wastewater Technologies (BD+C), and can be used if the two conditions of LEED Interpretation 10117 are met: 1) the seawater is municipally supplied or explicitly approved by the municipality and 2) meets all applicable codes and permitting requirements, so as not to contaminate the municipal wastewater system with high salinity. For EBOM projects, where no wastewater credit is available, the project may apply for innovation credit for use of this strategy.

**Update October 1, 2013: Note that LEED Interpretation 10117 has been updated to clarify that seawater must be treated to appropriate levels for non-potable uses in order to apply to WEc2 Innovative Wastewater Technologies; seawater that is treated to potable drinking water standards would not apply. Any on-site energy use to desalinate the seawater must be included in the EAp2/c1 calculations. Refer to the guidance document. Applicability of Seawater in Water Efficiency credits also updated.

Original ruling July 1, 2012
No, municipally supplied sources of non-potable water, including seawater, are not applicable to the WE fixture water use reduction credits, including WEp1 (D+C, EBOM) and WEc1 (CI) Water Use Reduction, or considered graywater. As stated in LI 1551 (12/12/2006) This credit focuses on fixture efficiency and on-site water reuse. In addition, the Water Use Reduction Additional Guidance document (updated 8/16/2010, http://www.usgbc.org/ShowFile.aspx?DocumentID=6493), confirms that the focus of the prerequisite is water efficiency of the installed fixtures, regardless of the water source, and only on-site water reuse is available as an alternative compliance path.
However, municipally treated wastewater (including treated seawater) applies to SSc1 - Path 9 Innovative Wastewater Technologies (CI), WEc2, Innovative Wastewater Technologies (BD+C), and can be used if the two conditions of LEED Interpretation 10117 are met: 1) the seawater is municipally supplied or explicitly approved by the municipality and 2) meets all applicable codes and permitting requirements, so as not to contaminate the municipal wastewater system with high salinity. For EBOM projects, where no wastewater credit is available, the project may apply for innovation credit for use of this strategy."

Campus Applicable
No
Internationally Applicable:
No
11/1/2011
LEED Interpretation
Inquiry:

Does a single-occupant lockable bathroom in a commercial establishment count as "private" for flush & flow rate calculations?

Ruling:

The project team is requesting a ruling on whether restrooms at a commercial establishment that are only usable by one individual or family at a time are considered private or private-use facilities. The facilities that are usable by one individual or family at a time at a commercial establishment are not considered private or private-use facilities. The private or public categories for lavatory faucets are based on the UPC and IPC Standards for plumbing fixtures, and are referring to the anticipated uses and performance expectations of such faucets. Public restroom faucets are used almost exclusively for hand washing or simple rinsing, compared to lavatory faucets in homes and in other private bathrooms that are used for various purposes. Therefore the single occupancy restroom facilities at a commercial establishment are not private-use facilities and the baseline case must be calculated according to the public lavatory faucet baseline flow rate. Applicable internationally.

Campus Applicable
No
Internationally Applicable:
Yes
7/2/2009
LEED Interpretation
Inquiry:

Our project has made water efficiency a high priority and has elected to install 0.5 GPM flow restrictors with occupancy sensors on all lavatory faucets, waterless urinals and dual flush toilets throughout. In our analysis regarding whether to continue our application under the LEED CI version 2 system or switch over to LEED CI v2009, we were surprised to find out that we would not be able to reach the 30% threshold and would therefore not be able to achieve any points for WEc1 under the version 2009 system, despite the fact that we have selected some of the most efficient fixtures available on the market. Using the fixtures listed above, we are able to achieve 45.9% savings under the v2 system, but only 29% savings under the new system due to the fact the baseline flow rate for lavatories under the v2009 system is 0.5 GPM instead of 2.2 GPM. In essence, the bar is set higher under the new system, but the baseline flow rate for lavatories is also much more stringent, making it near impossible to achieve points under this credit without the use of composting toilets, gray water systems or rainwater systems - which are not allowed by high rise buildings in our area. We have two questions: 1) Given the fact that it will be near impossible for the majority of LEED CI project to achieve points for WEc1 under the v2009 system despite selecting the most efficient fixtures on the market, we\'d like to ask the USGBC to reconsider the threshold for achieving points, particularly since the baseline for faucets in v2009 changed significantly. We suggest lowering the first v2009 threshold for points to 25% water savings which would allow projects that use 1/8 gallon, high efficiency urinals to potentially earn points. An alternative solution would be to use the same baseline as version 2, while keeping the raised v2009 threshold at 30% savings. 2) If you are not willing to reconsider the threshold or adjust the baseline for faucets, please advise how we might achieve points for WEc1 under the v2009 system in cases where composting toilets, gray water systems and rain water catchment system are not allowed. Keep in mind we\'re already using 0.5 GPM flow restrictors and occupancy sensors on all faucets, waterless urinals and dual flush toilets throughout.

Ruling:

The project is requesting the USGBC to revise the thresholds that have been established for the LEED-2009 rating system. The model plumbing codes requires .5 GPM or .25 GPC for public use (See footers of LEED 2009 Design and Construction Reference Guide). Part of the goal of the LEED rating system is to transform the marketplace towards a more sustainable building practice. As the market transforms and old best practices become standard practice, LEED also continues to evolve and raise the bar to continue its mission of transforming the marketplace towards a more sustainable built environment. LEED credits are established through a collaborative and iterative process of many stakeholders, opened for public comment, and balloted and approved by the USGBC member organizations. Those who wish to make changes to the rating system are encouraged to become involved in that process. If the project team is limited by code requirements, scope of project or other restrictions from implementing strategies that will allow the project to achieve additional points under Water Efficiency Credit 1 for LEED 2009, than the project may be unable to pursue those additional credits. Given the varying scope of projects, not all credits may be achievable for all projects. Furthermore, it appears that the design team has not considered the alternative baseline for commercial faucets, that of 0.25 gallons per cycle. The consideration of this baseline allows for other technology avenues for water use reduction. It should be noted that the purpose of the Water Efficiency credits is to reduce the Volume of potable water consumed. Volume is dependent upon two variables, flow rate and time (V=RT). In addition to a focus on volume, several strategies that control the time factor are also available. Finally, dual-flush toilets are a behavioral solution representing only one technology path out of many that could yield savings over the baseline, all of which are non-behavioral and subject to independent timed controls. Applicable Internationally.

Campus Applicable
No
Internationally Applicable:
Yes
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Requirements

Employ strategies that in aggregate use less water than the water use baseline calculated for the tenant spaces (not including irrigation). The minimum water savings percentage for each point threshold is as follows:

Percentage Reduction

Points

30%

6

35%

8

40%

11

Calculate the baseline according to the commercial and/or residential baselines outlined below. Calculations are based on estimated occupant usage and must include only the following fixtures and fixture fittings necessary to meet the needs of the occupants including fixtures and fixture fittings that may be outside the tenant space: water closets, urinals, lavatory faucets, showers, kitchen sink faucets and pre-rinse spray valves. [Europe ACP: Water Use Baseline]

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: 13.5 lpf

Commercial urinals

1.0 (gpf)

4.0 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

Commercial prerinse spray valves
(for food service applications)

Flow rate ≤ 1.6 (gpm)
(no pressure specified; no performance requirement)

Flow rate ≤ 6 lpm (no pressure specified; no performance requirement)

Residential Fixtures, Fittings, and Appliances

Current Baseline (Imperial Units)

Current Baseline (Metric Units)

Residential toilets

1.6 (gpf)***

6 liters per flush (lpf)

Residential lavatory (bathroom) faucets

2.2 (gpm) at 60 psi

8.5 lpm at 4 bar (58 psi)

Residential kitchen faucet

Residential showerheads

2.5 (gpm) at 80 (psi) per shower stall****

9.5 lpm  at 5.5 bar (80 psi) per shower stall

 

*       EPAct 1992 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/9.5 lpm) 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 water 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

Alternative Compliance Paths (ACPs)

Europe ACP: Water Use Baseline
Projects in Europe may use the values defined by European Standards. [view:embed_resource=page_1=4887984]

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