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LEED v2009
Existing Building Operations
Water Efficiency
Additional Indoor Plumbing Fixture and Fitting Efficiency

LEED CREDIT

EBOM-2009 WEc2: Additional Indoor Plumbing Fixture and Fitting Efficiency 1-5 points

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© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To maximize indoor plumbing fixture and fitting efficiency within buildings to reduce the use of potable water and consequent burden on municipal water supply and wastewater systems.

Requirements

During the performance period, have in place strategies and systems that in aggregate produce a reduction in indoor plumbing fixture and fitting potable water use from the calculated baseline established in WE Prerequisite 1: Minimum Indoor Plumbing Fixture and Fitting Efficiency. The minimum water reduction percentage for each point threshold is as follows:

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Cost estimates for this credit

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Frequently asked questions

If manufacturer documentation is unavailable and the flow/fixture rate is unknown, how would one go about confirming the flow/flush rates of those fixtures?

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We are not able to locate the flow/flush rates of the plumbing fixtures in the project building, so we have decided to test 20% of the fixtures of each fixture type. How do we go about doing that?

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If pre-1993 plumbing fixtures are still in place (i.e. the water closets), but their flush valves have been replaced post-1993, does that count as 'plumbing renovation' or fixture replacement for the purposes of the prerequisite/credit?

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See all forum discussions about this credit »

Addenda

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
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:

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
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:

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
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
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
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
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
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 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
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Intent

To maximize indoor plumbing fixture and fitting efficiency within buildings to reduce the use of potable water and consequent burden on municipal water supply and wastewater systems.

Requirements

During the performance period, have in place strategies and systems that in aggregate produce a reduction in indoor plumbing fixture and fitting potable water use from the calculated baseline established in WE Prerequisite 1: Minimum Indoor Plumbing Fixture and Fitting Efficiency. The minimum water reduction percentage for each point threshold is as follows:

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If manufacturer documentation is unavailable and the flow/fixture rate is unknown, how would one go about confirming the flow/flush rates of those fixtures?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

We are not able to locate the flow/flush rates of the plumbing fixtures in the project building, so we have decided to test 20% of the fixtures of each fixture type. How do we go about doing that?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

If pre-1993 plumbing fixtures are still in place (i.e. the water closets), but their flush valves have been replaced post-1993, does that count as 'plumbing renovation' or fixture replacement for the purposes of the prerequisite/credit?

The answer to this question is available to LEEDuser premium members. Start a free trial »

(If you're already a premium member, log in here.)

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
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:

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
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:

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
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
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
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
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
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."

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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 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

LEEDuser expert

Dan Ackerstein

Ackerstein Sustainability, LLC
Principal

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