The links below contain guidelines for achieving each goal, including recommended processes for each design phase.
WE Prerequisite 1: Water Use Reduction
WEp1 ROADMAP
| Design Phase | Recommended Approach: Activities | Recommended Approach: Responsibilities |
|---|---|---|
| Pre-Design | Set the goal of at least a 40% potable water reduction. | Client |
| Conceptual Design | Review WEp1 requirements. Calculate baseline water use based on FTE count and EPAct of 1992 requirements. Calculate the design case with fixtures that exceed EPAct of 1992 requirements. | Engineers |
| Schematic through Construction Documents | Calculate design use for sewage conveyance. Include water-efficient plumbing fixture requirements in the project specifications. Specify dual-flush toilets, low-flow lavatories with automatic faucets, and waterless urinals. If applicable, specify water-efficient kitchen dishwashers or washing machines. Consider composting toilets. See the Technologies & Products section for products and systems used at Harvard. | Engineers |
| Schematic Design | Consider using rainwater for flushing toilets. A dual-plumbing system is necessary for greywater reuse. Identify the amount of water that could be collected from interior greywater, or stormwater, for flushing toilets. | Architect/Engineers |
| Construction Documents | Complete LEED Online Letter Template and provide submittal requirements. | Engineers or OFS |
| Construction Documents to Construction | Ensure dual-flush toilets, low-flow lavatories with automatic faucets, and waterless urinals are specified. Ensure submittals are reviewed and approved per the specifications requirements. | Engineers |
| Construction Documents | This credit is a Design Submittal and should be submitted to the USGBC after construction documents are complete. | OFS or LEED Consultant |
| Construction | Review Contractor submittals to ensure water efficient fixtures are selected. | Engineers |
Design Intent and Sustainability Principles
Potable water is a limited natural resource, and increasing water efficiency in buildings conserves this resource and reduces the burden on municipal water supply and wastewater systems.
Financial Considerations
Water-saving fixtures, such as dual-flush toilets, waterless urinals, low-flow faucets and showerheads are comparable in price to standard fixtures, and have been used in numerous Harvard buildings. See the Technologies & Products section for more details.
LEED Requirements
LEED-NC Version 3
Employ strategies that in aggregate use 20% less water than the water use baseline calculated for the building (not including irrigation).
Calculate the baseline according to the commercial and/or residential baselines outlined below.1 Calculations are based on estimated occupant usage and must include only the following fixtures and fixture fittings (as applicable to the project scope): water closets, urinals, lavatory faucets, showers, kitchen sink faucets and prerinse spray valves.
| Commercial Fixtures, Fittings, and Appliances | Current Baseline |
|---|---|
| Commercial toilets | 1.6 gallons per flush (gpf)* Except blow-out fixtures: 3.5 (gpf) |
| Commercial urinals | 1.0 (gpf) |
| 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 |
| Commercial prerinse spray valves (for food service applications) |
Flow rate ≤ 1.6 (gpm) (no pressure specified; no performance requirement) |
| Residential Fixtures, Fittings, and Appliances | Current Baseline |
|---|---|
| Residential toilets | 1.6 (gpf)*** |
| Residential lavatory (bathroom) faucets | 2.2 (gpm) at 60 psi |
| Residential kitchen faucet | |
| Residential showerheads | 2.5 (gpm) at 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 (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) per shower compartment, where the floor area of the shower compartment is less than 2,500 square inches. For each increment of 2,500 square inches 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
LEED Submittals
LEED-NC Version 3
- "Determine the type and number of occupants
- Retain manufacturers' data showing the water consumption rates, manufacturer, and model of each fixture and fitting.
- List plumbing fixtures by usage group, if applicable.
- Define any usage groups."
- LEED-NC version 3 Reference Guide, page 174
(Complete descriptions of documentation requirements are on LEED-Online)
WEc1: Water Efficient Landscaping
WEc1 ROADMAP
| Design Phase | Recommended Approach: Activities | Recommended Approach: Responsibilities |
|---|---|---|
| Conceptual Design | Evaluate the site for use of native species, captured rainwater/greywater, efficient irrigation, and drought tolerant species. | Landscape Architect |
| Schematic Design | Specify native and adapted plants, to eliminate the need for a permanent irrigation system. | Landscape Architect |
| Schematic Design | Calculate the project's baseline and design total potable water applied annually. Ensure the design case is at least 50% better than the baseline case (2 points) or that NO potable water is used for irrigation (4 points). | Landscape Architect |
| Schematic Design | If needed, calculate life cycle costing to evaluate irrigation systems options. Use efficient irrigation systems. If irrigation is needed, consider rainwater harvesting. Provide space for a cistern. | Landscape Architect |
| Construction Documents | Complete Letter Template. Provide submittal requirements. | Landscape Architect |
| Construction Documents | This credit can be submitted with the Design Submittal, before construction is completed. | OFS or LEED Consultant |
Design Intent and Sustainability Principles
The intent of this credit is to reduce the quantity of potable water used for campus landscaping through the inclusion of native plant species, which rely on local annual rainfall and do not require extra irrigation after their initial plantings are established. Potable water is a precious resource, and its conservation on campus is a key tenet of the Harvard University Sustainability Principles. By conserving potable water, Harvard University is "demonstrating institutional practices that promote sustainability, including measures to increase efficiency."
Financial Considerations
According to the Davis Langdon study, water-efficient landscaping credits have very small construction and soft cost implications (Matthiessen, Fay and Morris, 15). There is potential for significant water savings at Harvard by reducing or eliminating the need for irrigation. The Harvard Business School (HBS) installed a weather monitoring station to water plantings only when necessary. HBS saves about $43,000 annually in water costs through decreased consumption. HBS used the Harvard Green Campus Loan Fund to finance the irrigation project, which had a payback of 4.93 years. It should be noted that a rain shut-off device does not qualify for the LEED credit 1.1.
LEED Requirements
See updated Credit Interpretation Rulings issued by the U.S. Green Building Council.
LEED-NC Version 3
OPTION 1. Reduce by 50% (2 points)
Reduce potable water consumption for irrigation by 50% from a calculated midsummer baseline case.
Reductions must be attributed to any combination of the following items:
- Plant species, density and microclimate factor
- Irrigation efficiency
- Use of captured rainwater
- Use of recycled wastewater
- Use of water treated and conveyed by a public agency specifically for nonpotable uses
Groundwater seepage that is pumped away from the immediate vicinity of building slabs and foundations may be used for landscape irrigation to meet the intent of this credit. However, the project team must demonstrate that doing so does not affect site stormwater management systems.
OR
OPTION 2. No Potable Water Use or Irrigation1 (4 points)
Meet the requirements for Option 1.
AND
PATH 1
Use only captured rainwater, recycled wastewater, recycled graywater or water treated and conveyed by a
public agency specifically for nonpotable uses for irrigation.
OR
PATH 2
Install landscaping that does not require permanent irrigation systems. Temporary irrigation systems used
for plant establishment are allowed only if removed within 1 year of installation.
1 If the percent reduction of potable water is 100% AND the percent reduction of total water is equal to or greater than 50%, both Option 1 and Option 2 are earned.
- LEED 2009 for New Construction and Major Renovations Rating System, page 23
LEED-NC Version 2.2
Previous LEED point: WEc1.1: Water Efficient Landscaping: Reduce by 50%
"Reduce potable water consumption for irrigation by 50% from a calculated mid-summer baseline case. Reductions shall be attributed to any combination of the following items:
- Plant species factor
- Irrigation efficiency
- Use of captured rainwater
- Use of recycled wastewater
- Use of water treated and conveyed by a public agency specifically for non-potable uses"
- LEED-NC Version 2.2 Reference Guide, page 115
Previous LEED point: WEc1.2: Water Efficient Landscaping: No Potable Water Use or No Irrigation
"Achieve WE Credit 1.1.and:
Use only captured rainwater, recycled wastewater, recycled greywater, or water treated and conveyed by a public agency specifically for non-potable uses for irrigation.
OR
Install landscaping that does not require permanent irrigation systems. Temporary irrigation systems used for plant establishment are allowed only if removed within one year of installation."
- LEED-NC Version 2.2 Reference Guide, page 127
LEED-NC Version 2.1
Previous LEED point: WE c1.1: Water Efficient Landscaping: Reduce by 50%
"Use high-efficiency irrigation technology OR use captured rain or recycled site water to reduce potable water consumption for irrigation by 50% over conventional means."
- LEED-NC Version 2.1 Reference Guide, page 81
Previous LEED point: WE c1.2: Water Efficient Landscaping: No Potable Use or No Irrigation
"Use only captured rain or recycled site water to eliminate all potable water use for site irrigation (except for initial watering to establish plants), OR do not install permanent landscape irrigation systems."
- LEED-NC Version 2.1 Reference Guide, page 82
LEED Submittals
[90 Mount Auburn Native Planting]
LEED-NC Version 3
- "Perform calculations of the baseline and design case to show the percentage reduction in water demand, and report what portion of irrigation will come from each nonpotable source (if any).
- Prepare a landscape plan showing a planting schedule and irrigation system."
- LEED-NC version 3 Reference Guide, page 187
(Complete descriptions of documentation requirements are on LEED-Online)
LEED-NC Version 2.2
Previous LEED point: WEc1.1: Water Efficient Landscaping: Reduce by 50%
- "The project's calculated baseline Total Water Applied (TWA) (gal). This data can be obtained using Equation 5. (from the Reference Guide cited)
- The project's calculated design case Total Water Applied (TWA) (gal). This data can be obtained using Equation 5. (from the Reference Guide cited)
- The total non-potable water supply (gal) available for irrigation purposes.
- Narrative describing the landscaping and irrigation design strategies employed by the project; description of the water-use calculation methodology used to determine savings; and for projects using non-potable water, specific information regarding source and available quantity of non-potable supplies."
-LEED-NC Version 2.2 Reference Guide, page 122-123
Previous LEED point: WEc1.2: Water Efficient Landscaping: No Potable Use or No Irrigation
- "The project's calculated baseline Total Water Applied (TWA) (gal). This data can be obtained using Equation 5. (from the Reference Guide cited)
- The project's calculated design case Total Water Applied (TWA) (gal). This data can be obtained using Equation 5. (from the Reference Guide cited)
- The total non-potable water supply (gal) available for irrigation purposes.
- Narrative describing the landscaping and irrigation design strategies employed by the project; description of the water-use calculation methodology used to determine savings; and for projects using non-potable water, specific information regarding source and available quantity of non-potable supplies."
- LEED-NC Version 2.2 Reference Guide, page 122-123
LEED-NC Version 2.1
Previous LEED point: WEc1.1: Water Efficient Landscaping: Reduce by 50%
"Provide the LEED Letter Template, signed by the architect, engineer or responsible party, declaring that potable water consumption for site irrigation has been reduced by 50%. Include a brief narrative of the equipment used and/or the use of drought-tolerant or native plants."
- LEED-NC Version 2.1 Reference Guide, page 81
Previous LEED point: WEc1.2: Water Efficient Landscaping: No Potable Use or No Irrigation
- "Provide the LEED Letter Template, signed by the responsible architect and/or engineer, declaring that the project site will not use potable water for irrigation. Include a narrative describing the captured rain system, the recycled site water system, and their holding capacity. List all the plant species used. Include calculations demonstrating that irrigation requirements can be met from captured rain or recycled site water.
OR
- Provide the LEED Letter Template, signed by the landscape architect or responsible party, declaring that the project site does not have a permanent landscape irrigation system. Include a narrative describing how the landscape design allows for this."
- LEED-NC Version 2.1 Reference Guide, page 82
Additional Resources
WEc2: Innovative Wastewater Technologies
WEc2 ROADMAP
| Design Phase | Recommended Approach: Activities | Recommended Approach: Responsibilities |
|---|---|---|
| Pre-Design | Incorporate innovative wastewater technologies into the sustainability and water efficiency project goals. | Client |
| Conceptual Design | Examine the possibility of integrating innovative systems into the stormwater management plan by reusing stormwater, collecting condensate, or using greywater for sewer conveyance. Coordinate water collection, treatment, storage, and reuse. An extra Innovation and Design credit is available for projects that reduce sewage conveyance potable water by 100% or treat 100% of wastewater on-site. Coordinate with MEP and/or the Civil Engineer to identify existing plumbing infrastructure. | Landscape/MEP |
| Conceptual Design/Schematic | Use life cycle costing to evaluate various plumbing options. | Landscape/MEP |
| Design Development | Calculate the number of FTE and baseline use for sewage conveyance. Calculate design use for sewage conveyance. Include water-efficient plumbing fixture requirements in the project specifications. | Landscape/MEP |
| Construction Documents | Complete LEED Letter Template and provide submittal requirements. | MEP |
| Construction Documents | This credit is a Design Submittal and should be submitted to the USGBC after Construction Documents are complete. | OFS or LEED Consultant |
| Construction | Review Contractor submittals to ensure water efficient fixtures are selected. | MEP |
Design Intent and Sustainability Principles
The intent of this credit is to reduce potable water demand for sewage conveyance. With its focus on the conservation of potable water, this credit challenges design teams to support long-term economic, environmental and socially responsible decision-making, which is the fourth Harvard University Sustainability Principle.
Financial Considerations
This credit presents an opportunity to examine feasibility through comparing capital and operating costs. The capital cost to reuse greywater increases with the need for a double plumbing system, and possibly containment systems, and the need to meet local code requirements. However, the reduction in potable water used to convey sewage reduces operating costs. Use of collected rainwater is less expensive. Reclaimed storm drainage water for sewage conveyance was considered at Five Cowperthwaite, but was eliminated during value engineering due to the 27.5 year payback. The wastewater reduction would have been 117%. One Western Avenue considered using greywater for water closets. The team considered collecting the water from sinks and showers, and carrying it to a holding tank and treatment system. The savings associated with this strategy was approximately $8,400 per year (in May 2001).
LEED Requirements
[Composting diagram from USGS]
See updated Credit Interpretation Rulings issued by the U.S. Green Building Council.
LEED-NC Version 3
"OPTION 1
Reduce potable water use for building sewage conveyance by 50% through the use of water-conserving fixtures
(e.g., water closets, urinals) or nonpotable water (e.g., captured rainwater, recycled graywater, on-site or
municipally treated wastewater).
OR
OPTION 2
Treat 50% of wastewater on-site to tertiary standards. Treated water must be infiltrated or used on-site."
- LEED 2009 for New Construction and Major Renovations Rating System, page 25
LEED-NC Version 2.2
"OPTION 1
Reduce potable water use for building sewage conveyance by 50% through the use of water conserving fixtures (water closets, urinals) or non-potable water (captured rainwater, recycled greywater, and on-site or municipally treated wastewater).
OR
OPTION 2
Treat 50% of wastewater on-site to tertiary standards. Treated water must be infiltrated or used on-site."
- LEED for New Construction Version 2.2, page 28
LEED-NC Version 2.1
"Reduce the use of municipally provided potable water for building sewage conveyance by a minimum of 50%, OR treat 100% of wastewater on site to tertiary standards."
- LEED-NC Version 2.1 Reference Guide, page 91
* An Innovation and Design credit is available for this element, if a project eliminates the use of potable water for sewage conveyance, or treats all wastewater on-site.
LEED Submittals
[Greywater diagram from EPA]
LEED-NC Version 3
- "Determine the type and number of occupants
- Retain manufacturers' data showing the water consumption rates, manufacturer, and model of each fixture and fitting.
- Compile information about system schematics and capacity of any rainwater or graywater systems."
- LEED-NC version 3 Reference Guide, page 197
(Complete descriptions of documentation requirements are on LEED-Online)
LEED-NC Version 2.2
- "Upload the applicable plumbing drawings from the construction documents that provide data regarding any on-site wastewater treatment facilities.
- The project's calculated occupants. The template will use a default one-to-one men to women ration. Projects with special occupancy situations that may result in an unbalanced ration may enter project specific data for this credit.
- The project's calculated baseline water usage for sewage conveyance. This data is calculated using typical fixture types (provided in the template) and the project's mix of occupants. Note: project teams must provide the following fixture information for each typical installed fixture type: fixture manufacturer, fixture model, flush rate in gallons per flush (gpf).
- For projects using non-potable water for sewage conveyance, provide the total non-potable water supply (gal) available for sewage conveyance purposes
- For projects treating wastewater on-site, provide the annual quantity (gal) of water treated, the annual quantity (gal) of treated water that is infiltrated, and the annual quantity (gal) of treated water that is re-used on site.
- Narrative describing the potable water reduction strategies employed by the project. For projects using non-potable water, include specific information regarding any reclaimed water usage (greywater re-use/rainwater reuse/on-site or municipally treated wastewater). If the project is treating wastewater on-site to tertiary standards, include specific information regarding the use(s) of the treated wastewater."
-LEED-NC Version 2.2 Reference Guide, page 133
LEED-NC Version 2.1
- "Provide the LEED Letter Template, signed by the architect, MEP engineer or responsible party, declaring that water for building sewage conveyance will be reduced by at least 50%. Include the spreadsheet calculation and a narrative demonstrating the measures used to reduce wastewater by at least 50% from baseline conditions.
OR
- Provide the LEED Letter Template, signed by the civil engineer or responsible party, declaring that 100% of wastewater will be treated to tertiary standards on site. Include a narrative describing the on-site wastewater treatment system."
- LEED-NC Version 2.1 Reference Guide, page 91
Additional Resources
WEc3: Water Use Reduction
WEc3 ROADMAP
| Design Phase | Recommended Approach: Activities | Recommended Approach: Responsibilities |
|---|---|---|
| Pre-Design | Set the goal of at least a 40% potable water reduction. | Client |
| Conceptual Design | Review WEc3 requirements. Calculate baseline water use based on FTE count and EPAct of 1992 requirements. Calculate the design case with fixtures that exceed EPAct of 1992 requirements. | Engineers |
| Schematic through Construction Documents | Calculate design use for sewage conveyance. Include water-efficient plumbing fixture requirements in the project specifications. Specify dual-flush toilets, low-flow lavatories with automatic faucets, and waterless urinals. If applicable, specify water-efficient kitchen dishwashers or washing machines. Consider composting toilets. See the Technologies & Products section for products used at Harvard. | Engineers |
| Schematic Design | Consider using rainwater for flushing toilets. A dual-plumbing system is necessary for greywater reuse. Identify the amount of water that could be collected from interior greywater, or stormwater, for flushing toilets. | Architect/Engineers |
| Construction Documents | Complete LEED Online Letter Template and provide submittal requirements. | Engineers or OFS |
| Construction Documents to Construction | Ensure dual-flush toilets, low-flow lavatories with automatic faucets, and waterless urinals are specified. Ensure submittals are reviewed and approved per the specifications requirements. | Engineers |
| Construction Documents | This credit is a Design Submittal and should be submitted to the USGBC after construction documents are complete. | OFS or LEED Consultant |
| Construction | Review Contractor submittals to ensure water efficient fixtures are selected. | Engineers |
Design Intent and Sustainability Principles
Potable water is a limited natural resource, and increasing water efficiency in buildings conserves this resource and reduces the burden on municipal water supply and wastewater systems.
Financial Considerations
Water-saving fixtures, such as dual-flush toilets, waterless urinals, low-flow faucets and showerheads are comparable in price to standard fixtures, and have been used in numerous Harvard buildings. See the Technologies & Products section for more details.
LEED Requirements
See updated Credit Interpretation Rulings issued by the U.S. Green Building Council.
LEED-NC Version 3
"Employ strategies that in aggregate use less water than the water use baseline calculated for the building (not including irrigation). The minimum water savings percentage for each point threshold is as follows:
Percentage Reduction |
Points |
|---|---|
30% |
2 |
35% |
3 |
40% |
4 |
Calculate the baseline according to the commercial and/or residential baselines outlined below.1 Calculations are based on estimated occupant usage and must include only the following fixtures and fixture fittings (as applicable to the project scope): water closets, urinals, lavatory faucets, showers, kitchen sink faucets and pre-rinse spray valves.
| Commercial Fixtures, Fittings, and Appliances | Current Baseline |
|---|---|
| Commercial toilets | 1.6 gallons per flush (gpf)* Except blow-out fixtures: 3.5 (gpf) |
| Commercial urinals | 1.0 (gpf) |
| 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 |
| Commercial prerinse spray valves (for food service applications) |
Flow rate ≤ 1.6 (gpm) (no pressure specified; no performance requirement) |
| Residential Fixtures, Fittings, and Appliances | Current Baseline |
|---|---|
| Residential toilets | 1.6 (gpf)*** |
| Residential lavatory (bathroom) faucets | 2.2 (gpm) at 60 psi |
| Residential kitchen faucet | |
| Residential showerheads | 2.5 (gpm) at 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 (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) per shower compartment, where the floor area of the shower compartment is less than 2,500 square inches. For each increment of 2,500 square inches 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. |
|
1 Tables adapted from information developed and summarized by the U.S. Environmental Protection Agency (EPA) Office of Water based on requirements of the Energy Policy Act (EPAct) of 1992 and subsequent rulings by the Department of Energy, requirements of the EPAct of 2005, and the plumbing code requirements as stated in the 2006 editions of the Uniform Plumbing Code or International Plumbing Code pertaining to fixture performance."
- LEED 2009 for New Construction and Major Renovations Rating System, page 26
LEED-NC Version 2.2
"Employ strategies that in aggregate use 20% less water than the water use baseline calculated for the building (not including irrigation) after meeting the Energy Policy Act of 1992 fixture performance requirements. Calculations are based on estimated occupant usage and shall include only the following fixtures (as applicable to the building): water closets, urinals, lavatory faucets, showers and kitchen sinks."
[For credit 3.2, substitute 30%]
- LEED-NC Version 2.2 Reference Guide, page 137
LEED-NC Version 2.1
"Employ strategies that in aggregate use 20% less water than the water use baseline calculated for the building."
- LEED-NC Version 2.1 Reference Guide, page 99
LEED Submittals
[Dual-Flush Toilet at Hamilton Hall]
LEED-NC Version 3
- "Determine the type and number of occupants
- Retain manufacturers' data showing the water consumption rates, manufacturer, and model of each fixture and fitting.
- List plumbing fixtures by usage group, if applicable.
- Define any usage groups."
- LEED-NC version 3 Reference Guide, page 174
(Complete descriptions of documentation requirements are on LEED-Online)
LEED-NC Version 2.2
- " The project's calculated occupants. The template will use a default one-to-one men to women ration. Projects with special occupancy situations that may result in an unbalanced ration may enter project specific data for this credit.
- The project's calculated design case water usage (flush and flow fixtures.) This data is calculated using project specified fixture types and the project's mix of occupants. Note: project teams must provide the following fixture information for each typical installed flush fixture type: fixture manufacturer, fixture model, flush rate in gallons per flush (gpf), or flow rate in gallons per minute).
- The project's calculated baseline water usage (flush and flow fixtures.) This data is calculated using typical fixture types (provided in the template) and the project's mix of occupants.
- For projects using non-potable water for sewage conveyance, provide the total non-potable water supply (gal) available for sewage conveyance purposes.
- Narrative describing the potable water reduction strategies employed by the project. For projects using non-potable water, include specific information regarding any reclaimed water usage (greywater re-use/rainwater reuse/on-site treated wastewater."
- LEED-NC Version 2.2 Reference Guide, page 143
LEED-NC Version 2.1
“Provide the LEED Letter Template, signed by the MEP engineer or responsible party, declaring that the project uses 20% less water than the baseline fixtures performance requirements of the Energy Policy Act of 1992.
Provide the spreadsheet calculation demonstrating that water-consuming fixtures specified for the stated occupancy and use of the building reduce occupancy-based potable water consumption by 20% compared to baseline conditions."
- LEED-NC Version 2.1 Reference Guide, page 99
[For credit 3.2, substitute 30%]
Additional Resources
Updated: Wednesday, July 29, 2009 1:36 PM
