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LEED v4
Existing Buildings
Water Efficiency
Indoor water use reduction

LEED CREDIT

EBOM-v4 WEc2: Indoor water use reduction 2-5 points

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SPECIAL REPORT

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Dan Ackerstein

Ackerstein Sustainability, LLC
Principal

SPECIAL REPORT

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Credit language

USGBC logo

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

Intent

To reduce indoor water consumption.

Requirements

Option 1. Calculated water use (1–5 points except Data Centers, 1–4 points Data Centers)
Establishment
None.
Performance
Have fixtures that use less water than the baseline calculated in WE Prerequisite Indoor Water-Use Reduction. Points are awarded according to Table 1.
Table 1. Points for reducing calculated water use beyond the prerequisite level.
Additional percentage reduction Points (except data centers) Points (data centers)
10% 1 1
15% 2 2
20% 3 3
25% 4 4
30% 5 --
Confirm that calculations are up to date. Demonstrate that all purchases made since the end of the performance period meet the design performance requirements.

OR

Option 2. Metered water use (1-5 points except Data Centers, 1-4 points Data Centers)
Establishment
Meter fixtures and fittings, and record meter data for one year to establish a water-use baseline.
Performance
For projects with at least 80% of fixtures and fittings metered, show a reduction from the baseline year of meter data.
Table 2. Points for reducing metered water use
Percentage reduction Points (except data centers) Points (data centers)
1 1
5-10% 2 2
10-15% 3 3
15-20% 4 4
>20% 5 --
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Addenda

10/1/2014Updated: 12/3/2019
Reference Guide Correction
Description of change:
Replace "Projects in unlisted countries must comply with the 20%-below-baseline requirement but have no additional performance requirements" with: "Project outside the U.S. must meet WaterSense flush and flow rates."

In the related “International Water Labeling Programs” Guidance Document (http://www.usgbc.org/resources/international-water-labeling-programs), edit the note at the bottom of the document to read:
“Note: countries without a listed labeling program must meet the flush and flow requirements of “Table 6. Maximum installed flush or flow rates for prescriptive path” listed in the Step-by-Step Guidance section of the LEED Reference Guide.
Campus Applicable
No
Internationally Applicable:
Yes
4/6/2018Updated: 4/24/2018
Reference Guide Correction
Description of change:
Add the following content to the end of the "International Tips" section:

“Projects served by water supply pressures different than specified in LEED v4 may install pressure compensating aerators in flow fixtures to achieve the desired flow rate without compromising user satisfaction.”
Campus Applicable
No
Internationally Applicable:
Yes
1/27/2017Updated: 10/12/2017
Reference Guide Correction
Description of change:
BD+C, ID+C reference guide: Revise the Group Approach section to read: "Eligible. The percentage reduction can be based on the total combined water use reduction in all LEED project buildings. If nonpotable water systems will be shared by multiple projects, ensure adequate supply to meet the demands of all projects using nonpotable water. The nonpotable water may not be double-counted among projects. Submit separate documentation for each building, as required for WE Prerequisite Indoor Water Use Reduction. "

O+M reference guide: Revise the Group Approach section to read: "Eligible. The percentage reduction can be based on the total combined water use reduction in all LEED project buildings. The baseline adjustment for year of substantial system completion should be averaged based on all plumbing fixtures in all buildings. If nonpotable water systems will be shared by multiple projects, ensure adequate supply to meet the demands of all projects using nonpotable water. The nonpotable water may not be double-counted among projects. Submit separate documentation for each building, as required for WE Prerequisite Indoor Water Use Reduction. "
Campus Applicable
Yes
Internationally Applicable:
Yes
1/27/2017Updated: 1/27/2017
Form Update
Description of change:
modified flow fixture calculation to allow for savings on total daily water use from non-default duration (v03)
Campus Applicable
No
Internationally Applicable:
No
4/5/2016Updated: 4/7/2016
Reference Guide Correction
Description of change:
Revise the second sentence to read: “If the spaces use different fixtures or have dramatically different patterns of occupancy or varying annual days of operation, complete the indoor water use calculator with a separate fixture group for each space type.”
Campus Applicable
Yes
Internationally Applicable:
Yes
1/4/2016Updated: 1/5/2016
Reference Guide Correction
Description of change:
Step-by-step: remove the "All Projects" section and move these steps to Option 1 as Steps 4-7:

"Complete the steps below for the chosen option.
Option 1. Calculated Water Use (E and P)
Step 1. Determine baseline (E)...
Step 2. Gather information for calculator (E)...
Step 3. Complete calculations (E)...
Step 4. Inspect and repair all existing fixtures and fittings (E)
Make any repairs needed to bring all fixtures and fittings into good working order. Permanently turn off the water supply to any nonfunctional units.
Step 5. Create fixture and fitting replacement and retrofit policy (E)
Develop and implement a policy specifying that all newly installed toilets, urinals, private lavatory faucets, and showerheads that are eligible for labeling be WaterSense labeled (or a local equivalent for projects outside the U.S.).
If plumbing capacity is insufficient to support WaterSense fixtures, include a narrative explaining why WaterSense fixtures would not perform well.
Schools, Retail, and Hospitality projects must include applicable appliances in the building and under site management’s control.
Step 6. Document new purchases and installations (P)
Document any new purchases and installations of fixtures, fittings, and appliances to demonstrate compliance.
Demonstrate that all applicable fixture and/or fitting purchases made during the performance period meet the requirements of the fixture and fitting replacement and retrofit policy.
For Schools, Retail, and Hospitality projects, demonstrate that all applicable appliances purchased during the performance period meet the prerequisite requirements and replacement and retrofit policy.
Step 7. Confirm calculations (P)
Confirm that the calculations reflect the building’s current water use and recalculate as necessary."

Required documentation: change the table so that it is organized by option:

Documentation Option 1 Option 2
E Indoor water use calculator X
E Replacement and retrofit policy X
E,P Water meter data (baseline and performance period) X
P Calculations X
Campus Applicable
Yes
Internationally Applicable:
Yes
4/1/2015Updated: 4/1/2015
Reference Guide Correction
Description of change:
Add the following language to International Tips under the Further Explanation section:

"Pressure testing standards
Supply water pressure and flow rate pressure testing standards vary throughout the world. For consistency, it is recommended that all projects use the flow rates reported by the manufacturer at 60 psi (415 kPa) for lavatories and kitchen sinks and 80 psi (550 kPa) for showerheads, or obtain the rated flow rates from an independent testing company.

If the manufacturer or testing company cannot provide the rated flow rate, project teams may use on-site tests to report the most accurate volume of water use. The fixture performance baseline would be developed by testing a baseline fixture onsite in the context of the building water pressure. The design case would use the actual measured flow rate of the fixtures installed in the project. The underlying assumptions used for calculating projected water use savings must remain consistent between the baseline and design cases."
Campus Applicable
No
Internationally Applicable:
Yes
10/1/2014Updated: 2/14/2015
Form Update
Description of change:
Fixed errors in previous version including uses per day calculation. Added override functions for special circumstances, modified built-in dual flush calculator, added custom naming of tabs and streamlined output fields

Added Neighborhood Development calculations
Campus Applicable
No
Internationally Applicable:
Yes
1/27/2017
LEED Interpretation
Inquiry:

Can automated-maintenance urinals be considered "waterless" for the purposes of WE prerequisite and credit Indoor Water Use Reduction?

Ruling:

Yes, automated maintenance urinals with water use not to exceed 150 gallons (568 liters) annually can be considered as waterless urinals for the purposes of credit achievement calculations in LEED v4 WE prerequisite and credit Indoor Water Use Reduction. Do not include the volume of water used by these urinals in the LEED v4 Indoor Water Use Calculator (they can be excluded, or considered to have a water use of 0 gallons/liters). Projects must also submit manufacturer documentation showing the annual volume of water used by the urinals.

Campus Applicable
Yes
Internationally Applicable:
Yes
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Documentation toolkit

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LEEDuser’s Documentation Toolkit is loaded with calculators to help assess credit compliance, tracking spreadsheets for materials, sample templates to help guide your narratives and LEED Online submissions, and examples of actual submissions from certified LEED projects for you to check your work against. To get your plaque, start with the right toolkit.

LEEDuser expert

Dan Ackerstein

Ackerstein Sustainability, LLC
Principal

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USGBC logo

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

Intent

To reduce indoor water consumption.

Requirements

Option 1. Calculated water use (1–5 points except Data Centers, 1–4 points Data Centers)
Establishment
None.
Performance
Have fixtures that use less water than the baseline calculated in WE Prerequisite Indoor Water-Use Reduction. Points are awarded according to Table 1.
Table 1. Points for reducing calculated water use beyond the prerequisite level.
Additional percentage reduction Points (except data centers) Points (data centers)
10% 1 1
15% 2 2
20% 3 3
25% 4 4
30% 5 --
Confirm that calculations are up to date. Demonstrate that all purchases made since the end of the performance period meet the design performance requirements.

OR

Option 2. Metered water use (1-5 points except Data Centers, 1-4 points Data Centers)
Establishment
Meter fixtures and fittings, and record meter data for one year to establish a water-use baseline.
Performance
For projects with at least 80% of fixtures and fittings metered, show a reduction from the baseline year of meter data.
Table 2. Points for reducing metered water use
Percentage reduction Points (except data centers) Points (data centers)
1 1
5-10% 2 2
10-15% 3 3
15-20% 4 4
>20% 5 --

In the end, LEED is all about documentation. LEEDuser’s Documentation Toolkit, for premium members only, saves you time and helps you avoid mistakes with:

  • Calculators to help assess credit compliance.
  • Tracking spreadsheets for materials purchases.
  • Spreadsheets and forms to give to subs and other team members.
  • Guidance documents on arcane LEED issues.
  • Sample templates to help guide your narratives and LEED Online submissions.
  • Examples of actual submissions from certified LEED projects.

LEEDuser expert

Dan Ackerstein

Ackerstein Sustainability, LLC
Principal

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