LEED WE - Water Efficiency
Water Efficiency LEED WE encourages close availability to neighborhood services and mass transit
In the US 340 billion gallons of fresh water is withdrawn from our rivers, lakes and reservoirs. Almost 65% of this water is returned to the same bodies of water and in some cases it is now treated water.
In some parts of the US the aquifers have been recorded to have dropped over 100 feet. The water deficit in the US stands at about 3,700 billion gallons of water on an annual basis with self-supplied domestic withdrawals re estimated at 3,590 million gallons a day!
Water efficiency measures that are implemented in a LEED for homes home can account for a savings of approximately 30,000 gallons of water per year, which amounts to a savings of over $100.00 per year.
The Energy Policy Act of 1992 mandated the use of water-conserving plumbing fixtures to reduce water use in residential, commercial and institutional buildings, which is a great step forward.
The LEED WE Credit program is designed to bring conservation levels to new, never-before-attained levels. There are three types of credits available to the Project Teams and Home Owners.
They are Water Reuse, Irrigation Systems and Indoor Water Usage. Green Living Made Easy has addressed many of these issues within the pages of our web site.
We will direct you to the appropriate pages as you work through each of these Water Efficiency
LEED WE Categories:
Water Reuse: LEED WE 1
Irrigation System: LEED WE 2
Indoor Water Use: LEED WE 3
Total Points Available = 15 Points
Minimum Points Needed = 3
- WE 1.1
- WE 1.2
- WE 1.3
- WE 2.1
- WE 2.2
- WE 2.3
- WE 3.1
- WE 3.2
Use municipal recycled water or offset central water supply through the capture and controlled reuse of rainwater and/or gray-water.
None
Note: Rainwater and graywater capture systems are subject to local codes and may required special permits. Note that the water quality should meet local standards, and consult manufacturers' recommendations to determine the compatibility of plumbing fixtures with graywater. Many states and regulatory agencies require that water going into a toilet or sink meet potable water standards; builders should comply with local codes.
Design and install a rainwater harvesting and storage system (including surface runoff and/or roof runoff) for landscape irrigation use or indoor water use. The storage system must be sized to hold all the water from a 1-inch rainfall event (equivalent to 0.62 gallons per square foot of roof area used for capture), taking into consideration the size of the harvest system (i.e., 50% or 75% of total roof are, depending on the measure chosen from the table.<\
Hover HERE for table of Rainwater Harvesting
A rainwater harvesting system captures rainwater from the home site and roof and stores the water in a large cistern, or tank for later reuse. This type of system can significantly reduce or eliminate water use for outdoor irrigation or supply of gray water to indoor toilets and and clothes washers. Collecting water in this manner also reduces storm water related problems such as flooding and erosion.
Design the system with consideration to frequency and volume of local rainfall events, annually or seasonally.
A rainwater capture system has the following basic components: Note: Green Living Made Easy has a wealth of information on Rainwater Collection Systems.
- Catchment Area: Roof area or site drainage
- Conveyance Systems: Gutters, downspouts, diverters and piping that lead to the storage tank.
- Storage System: A tank, cistern or other opaque storage device to keep out direct sunlight and contaminates.
- Distribution System: The piping and/or pumps that connect the storage system to the end-use fixtures.
Determine the rainwater harvesting system size as a percentage of the total area of the roof. Hover mouse HERE for the Rainwater Harvesting Table.
Determine the Minimum Storage Capacity by this equation: Storage Capacity = 0.62 gallons/s.f. x Harvest Area.
Projects that install a system sized to capture water from 100% of the roof area can apply for 1 point. Apply Under LEED ID 3. This application must be submitted by the Provider and approved by USGBC before the point can be counted.
Trade: Provide calculations for system size and harvesting area to Building Team and Project Leader.
Builder/Project Team: Provide calculations to Green Rater. Include andy rainwater harvesting system equipment literature in the occupant's operations and maintenance manual.
Green Rater: Verify that calculations have been completed. Visually inspect that they have been installed correctly.
A project receiving points for WE 1.3 must skip WE 1.1 and WE 1.2.
Rainwater harvesting and graywater reuse irrigation systems should be integrated with resource-efficient landscape LEED SS 2 and irrigation system design LEED WE 2.
-AND/OR-
| System Size | Application | Points |
|---|---|---|
| >50% of Roof Area | Indoor Only | 2 |
| >50% of Roof Area | Outdoor Only | 3 |
| >75% of Roof Area | Indoor & Outdoor | 4 |
Use municipal recycled water or offset central water supply through the capture and controlled reuse of rainwater and/or graywater.
none
Design and install a graywater reuse system for landscape irrigation use (i.e., not a septic system) or indoor water use.The system must include a tank or dosing basin that can be used as part of the irrigation system. Graywater must be collected from at least one of the following:
- clothes washer
- showers;
- some combination of faucets and other sources estimated to exceed 5,000 gallons per year.
Gray-water is defined by the UPC (Uniform Plumbing Code) as untreated household wastewater which has not come into contact with toilet waste". This would include water discharged from bathtubs, shower, wash basins and clothes washer and laundry tubs. Not waste from Kitchen sinks or water closets, which must not be reused. This credit rewards the reuse of least 5,000 gallons of gray-water per year.
- Meet all state and local health codes with the designed gray-water system.
- Gray-water systems may require inspection and approval by local health officials.
- The use of gray-water systems plumbed to certain plumbing fixtures may void warranties.
- The gray-water system consists of the following components:
- 1. Plumbing System to capture the gray-water at its source, transfer it to a storage tank and distribute it.
- 2. Surge tank: The storage container, sized to hold at least one week of gray-water (roughly 100 gallons)
- 3. Filtration System: Gray-water treatment, if necessary, to minimize odors and bacteria growth.
None required for this LEED WE Credit.
Install a gray-water system that collects water from multiple elements can apply for 1 point under ID 3.
Trade: Provide calculation for the gray-water reuse system and surge tank size to Builder/Team Leader
Building/Project Team; Present gray-water calculations to Green Rater. Include any system equipment information in the occupant's operations and maintenance manual.
Green Rater: Verify that the calculations are completed properly Visually verify that gray-water system is installed properly.
A project receiving points for LEED WE 1.3 must skip LEED WE 1.1 and LEED WE 1.2.
Rainwater harvesting and graywater reuse irrigation systems should be integrated with resource-efficient landscape LEED SS 2 and irrigation system design LEED WE 2.
-OR-
None
Design the plumbing such that irrigation system water demand is supplied by municipal recycled water. This is applicable only in communities with a municipal recycled water Program
Note: A home using a municipal recycled water system cannot receive points under LEED WE 1.2 (Graywater Reuse System) or LEED WE 1.1 (Rainwater Harvesting System) for outdoor applications.
Municipalities across the country have begun to develop infrastructure for tertiary treatment of wastewater and storm water. This recycled or reclaimed water enables these communities to med their water demand without having to divert water from streams, lakes, rivers or aquifers. This water is safely treated to meet US Environmental Protection Agency regulations and depending on the level of treatment can be used for irrigation needs to drinking water use - be sure to check with local, state and county health organizations before proceeding. This credit reward a home that used only the municipal recycled water for 100% of its irrigation needs.
The plumbing in the home must be designed to separate the recycled water supply from the potable water supply The recycled water is typically circulated through "purple" lines to distinguish it from potable water lines. Consult local, county and state agencies to verify the use of recycled water.
None Required for this LEED WE Credit.
None
Building/Project Team; Provide evidence from the municipality that a recycled water system is in place. Include system equipment information in the homeowners maintenance manual
Green Rater: Visually verify that recycled water system is installed properly
A project receiving points for LEED WE 1.3 must skip LEED WE 1.1 and LEED WE 1.2.
Rainwater harvesting and graywater reuse irrigation systems should be integrated with resource-efficient landscape LEED SS 2 and irrigation system design LEED WE 2.
Minimize outdoor demand for water through water-efficient irrigation.
None
Design and install a high-efficiency irrigation system (based on overall landscaping plans, including measures adopted in SS2) such that any of the following are met.
- Install an irrigation system designed by an EPA WaterSense certified professional
- Design and install an irrigation system with head-to-head coverage.
- Install a central shut-off valve.
- Install a sub-meter for the irrigation system.
- Use drip irrigation for at least 50% of the landscape planting beds to minimize evaporation.
- Create separate zones for each type of bedding area based on watering needs.
- Install a timer or controller that activates the valves for each watering zone at the best time of day to minimize evaporative losses while maintaining healthy plants and obeying local regulations and water use guidance.
- Install pressure-regulating devices to maintain optimal pressure and prevent misting.
- Utilize high-efficiency nozzles with an average distribution uniformity of at least 0.70. This may include conventional rotors, multi-stream rotors, or high-efficiency spray heads. A drip source irrigation system should be counted as having a DU of 0.80.
- Check valves in heads.
-
Install a moisture sensor controller or rain delay controller. For example, "smart" evapotranspiration controllers receive radio, pager, or Internet signals to direct the irrigation system to replace only the moisture that the landscape has lost because of heat, wind, etc..
Outdoor irrigation usage accounts for over 30% of all water use in the US. Irrigation typically utilized potable water even though gray-water and recycled water systems are equally effective. Use these measure in increase the efficiency of your outdoor irrigation systems and using only as much water as necessary.
A home may not need an irrigation system. These credits reward any necessary irrigation systems that are designed and installed to be highly efficient.
- First of all determine whether an irrigation system is really required.
By utilizing drought-tolerant plants and native species plants, you can dramatically reduce the amount of water required for your landscape. If the site is designed not to receive irrigation a project can earn credits under SS2.5 and/or WE 2.3.
A well designed system uses head-to-head coverage and high-efficiency nozzles or drip irrigation to ensure that plantings receive enough water but no more than necessary. Strategies for taking into consideration the moisture requirements of the installed plants are awarded in LEED WE 2.1 (b), (e), and (i).
Controls, timers, and sensors enable "smart" irrigation systems to operate only when water is needed and conditions are optimal for watering. Flow sensors can also identify leaks or breaks. These strategies are awarded in LEED WE 2.1 (g), (h), and (k).
Valves are generally managed by the controls but also enable the system to be manually shut off when a leak opr problem occurs. The heads that distribute water vary in effectiveness. The best Strategies are awarded in LEED WE 2.1 (c) and (j).
Use multiple irrigation zones if the site is designed with different types of landscaping or if shading and wind exposure create different microclimates on the site.
None Required for this LEED WE Credit
A project can earn up to 2 additional exemplary Performance points by implementing additional measure from the list above. Gain 1/2 point per measure and they are counted toward ID 3.
Trade: Sign an accountability Form to indicate the system meets the credit requirements. Deliver literature to Project Team for insertion in Owners Maintenance Manual.
Building/Project Team; Include system equipment information in the homeowners maintenance manual.
Green Rater: Verify that the accountability form has been signed. Visually verify that irrigation system is installed properly.
A project receiving points for LEED WE 1.3 must skip LEED WE 1.1 and LEED WE 1.2.
Rainwater harvesting and graywater reuse irrigation systems should be integrated with resource-efficient landscape LEED SS 2 and irrigation system design LEED WE 2.
-AND/OR-
None
Perform third-party inspection of the irrigation system in operation, including observation of all of the following:
- All spray heads are operating and delivering water only to intended zones.
- Any switches or shut-off valves are working properly.
- Any timers or controllers are set properly
- Any irrigation systems are located at least 2 feet from the house.
- Irrigation spray does not hit the home
Provide Third Party Inspection of the irrigation system in operation, including observation of all of the following:
- All spray heads are operating and delivering water only to intended zones.
- Any switches or shut-off valves are set properly.
- Any timers or controllers are set properly.
- Any irrigation systems are located at leas 2 feet from the home.
- Irrigation spray does not hit the home structure.
First of all determine whether an irrigation system is really required. By utilizing drought-tolerant plants and native species plants, you can dramatically reduce the amount of water required for your landscape. If the site is designed not to receive irrigation a project can earn credits under SS2.5 and/or WE 2.3.
None
A project can earn up to 2 additional exemplary Performance points by implementing additional measure from the list above. Gain 1/2 point per measure and they are counted toward ID 3.
Trade: Sign an accountability Form to indicate the system meets the credit requirements.
Green Rater: Verify that the accountability form has been signed if by other than Green Rater.
A project receiving points for LEED WE 1.3 must skip LEED WE 1.1 and LEED WE 1.2.
Rainwater harvesting and graywater reuse irrigation systems should be integrated with resource-efficient landscape LEED SS 2 and irrigation system design LEED WE 2.
None
Design the landscape and irrigation system to reduce the overall irrigation water demand water budget. The estimates must be calculated and prepared by a landscape professional, biologist, or other qualified professional using the calculation method listed below:
Note: A project must earn full points in LEED SS 2.5 before receiving points for this credit.
With irrigation systems consuming approximately 30% of the total potable water in the US, a holistic approach to landscape design is to pick plants that demand less water, pick irrigation systems that are more efficient and utilize techniques in our landscaping that minimize evaporation of both rainwater and introduced water. This credit rewards projects that demonstrate less overall water usage when compared to a conventional irrigation system in use today.
- This credit is a performance based credit and is to be used along with LEED SS 2.5. You cannot combine with credits from SS 2.2, 2.3 and 2.4, and LEED WE 2.1 and LEED WE 2.2. Use either -or-.
Hover Mouse HERE for Reduction in Water Demand Table
- This credit provides more flexibility but requires more verification and calculations.
- Minimum water reduction of 20% and rewards for savings up to 45%. If over 45% you are eligible for WE 2.3.
- Choose vegetation that required little or no irrigation.
- Avoid turf grasses
- Use high-efficiency irrigation systems such as drip irrigation.
- Integrate rainwater, rainwater harvesting systems, gray-water irrigation systems etc. into your irrigation needs. However, these systems are rewarded in WE 1.1, 1.2, and 1.3, and any water demand being met by these systems must still be counted in the calculation for this credit.
Ensure that both the landscaping plan and the irrigation systems are installed per the plans.
-
1. Obtain Species Factor (Ks)Hover Mouse HERE for Species Factor Table.(Kmc)
-
2. Obtain Microclimate Factor. Hover Mouse HERE for Micro-Climate Factor Table.(Kmc)
-
3. Obtain Irrigation Efficiency (IE). Hover Mouse HERE for Irrigation Efficiency Table.(Kmc)
- 4. Obtain Evapotranspiration Rate (ET)
- 5. Calculate Product of Ks x Kmc = Kl
- 6. Calculate ET x Kl = ETl
- 7. Calculate Baseline Usage = Landscaped Area x ET x .62
- 8. Calculate Design Case Usage = (Landscaped Area x ETl/IE) x CF x .62
- 9. Calculate Percentage of Reduction = (1-Design Case Usage/Baseline Usage) x 100
Note: Value of CF is estimate value base on manufacturer's specification for percentage water savings.
- All irrigation calculations are base on the month of July.
- All estimates shall be for fully mature plants.
- Landscape Coefficient (Kl) indicate the volume of water lost via evapotranspiration.
- Species Factor (Ks) accounts for the water requirements of different plant species.
- Microclimate Factor(Kmc) accounts for environmental conditions specific to the landscape, including wind, sun, temperature and humidity.
- Baseline Evapotranspiration Rate (ET) represents the rate of water loss for a particular climate or region.
- Landscape Evapotranspiration Rate (ETl) is the site-specific rate, which is calculate based on other variables.
- Irrigation Efficiency (IE) is based on the type of irrigation equipment installed.
- Control Factor (CF) is based on the type of controls installed such as weather based or moisture sensors.
None
Trade:Provide calculations for the irrigation demand to the builder or project team leader. Provide a list of plants being used to the builder or project team leader. Sign an Accountability Form to indicate that the installed landscape and irrigation system correspond to the design used in the calculations.
Builder/Project Team: Present calculations to Green Rater. Present listing of plants to Green Rater.
Green Rater: Visually verify all calculations are completed. Verify accountability form is signed properly.
A project receiving points for LEED WE 1.3 must skip LEED WE 1.1 and LEED WE 1.2.
Rainwater harvesting and graywater reuse irrigation systems should be integrated with resource-efficient landscape LEED SS 2 and irrigation system design LEED WE 2.
| Water Reduction | SS2.5 Points | WE 2.3 Points | Total Points |
|---|---|---|---|
| 20-24% | 2 | 0 | 2 |
| 25-29% | 3 | 0 | 3 |
| 30-34% | 4 | 0 | 4 |
| 35-39% | 5 | 0 | 5 |
| 40-44% | 6 | 0 | 6 |
| 45-49% | 6 | 1 | 7 |
| 50-54% | 6 | 2 | 8 |
| 55-59% | 6 | 3 | 9 |
| > 60% | 6 | 4 | 10 |
| Vegetation Type | Low | Average | High |
|---|---|---|---|
| Trees | 0.2 | 0.5 | 0.9 |
| Shrubs | 0.2 | 0.5 | 0.7 |
| Gr. Cover | 0.2 | 0.5 | 0.7 |
| Turf | 0.6 | 0.7 | 0.8 |
| Micro-Climate Impacts | Low | Average | High |
|---|---|---|---|
| Shading | 0.5 | 0.8 | 1.0 |
| High Sun Exp. | 1.0 | 1.2 | 1.5 |
| Prot. From Wind | 0.8 | 0.9 | 1.0 |
| Windy Area | 1.0 | 1.2 | 1.5 |
| Irrigation Type | Low | High |
|---|---|---|
| Fixed Spray | 0.4 | 0.6 |
| Impact & Microspray | 0.5 | 0.7 |
| Rotors | 0.6 | 0.8 |
| Multistream Rotors | 0.6 | 0.8 |
| Drip Source | 0.7 | 0.9 |
None
Meet one or more of the following requirements by installing high-efficiency fixtures or fittings. A project cannot earn point in both LEED WE 3.1 and LEED WE 3.2 for the same fixture type.
Note: Compensating shower valves and conventional, non-compensating shower valves may not work properly when low-flow showerheads (restricting water flow below 2.5 gpm) are installed. Installing low-flow showerheads where compensating valves or conventional, non-compensating valves are installed can increase the risk of scalding (or other types of injuries, such as slips and falls due to thermal shock) when the plumbing system experiences pressure changes. Make sure any low-flow showerhead is installed with a valve that has been designed, tested, and verified to function safely at the reduced flow rate. If in doubt, consult the manufacturer of the valve before installing a low-flow showerhead.
- The average flow rate for all lavatory faucets must be <=2.0 gpm.
- The average flow rate for all showers must be <= 2.0 gpm per stall.
- The average flow rate for all toilets must be <= 1.3 gpf
-OR-
Toilets meet the US EPA WaterSense specification and be certified and labeled accordingly.
-OR-
Toilets must meet the US EPA WaterSense specification and be certified and labeled accordingly.
Faucets, showers, baths and toilets typically consume more than 60% of a home's total potable water use. The installation of high efficiency faucets, toilets and shower heads is a very easy strategy to reduce this indoor water use by consuming less than half of the more conventional fixtures. This credit rewards installation of either high-efficiency or very high efficiency fixtures and fittings in bathrooms.
- To the consumer the high-efficiency fixtures look exactly the same as conventional fixtures.
- Low-flow faucets achieve water savings by the use of aerators , which combine air with water to give the user the feeling that they are getting an equivalent water pressure buy with less water.
-
Low-flow showerheads should be installed with proverb thermostatic mixing valves that have been designed, tested and verified to function safely at the reduced flow rate.
- Not all high-efficiency toilets operate equally well, and poor design can lean to multiple flushes.
- Some high efficiency toilets have dual flush settings, one for liquid waste and the other for solid waste.
- Use caution when hooking up high efficiency fixtures to gray-water systems as this may void their warranty.
If a project includes multiple fixtures and fittings with different efficiencies, use a straight-line average to determine the overall average efficiency of each fixture type. For example, if tow lavatory faucets have flow rates of 1.5 gpm and a third is rated for 2.1 gpm, the average overall flow rate is equal to (1.5 + 1.5 + 2.1)/3 or 1.7 gallons per minute. For the purposes of this calculation, all dual-flush toilets should be treated as 1.25 gpm, or the high-flow volume, whichever is lower.
Projects which can verify flow rates substantially lower than the requirements for LEED WE 3.2 can earn 1 additional point, to be counted under Innovation & Design 3. The application must be submitted by the Provider and approved by USGBC before the point can be counted.
Trade: Deliver any equipment literature (e.g., user manuals, brochures, specifications) related to fixtures and fittings to the builder or team leader.
Builder/Project Team: Place any literature and other fixture information in the Owner Maintenance Manual.
Green Rater: Visually verify that all fixtures and equipment are installed and in operation.
A project receiving points for LEED WE 1.3 must skip LEED WE 1.1 and LEED WE 1.2.
Rainwater harvesting and graywater reuse irrigation systems should be integrated with resource-efficient landscape LEED SS 2 and irrigation system design LEED WE 2.
None
Meet one or more of the following requirements by installing high-efficiency fixtures or fittings. A project cannot earn point in both LEED WE 3.1 and LEED WE 3.2 for the same fixture type.
- The average flow rate for all lavatory faucets must be <=1.5 gpm.
-OR-
- Lavatory faucets must meet the US EPA WaterSense specification and be certified and labeled accordingly
- The average flow rate for all showers must be <= 1.75 gpm per stall.
- The average flow rate for all toilets must be <= 1.1 gpf
Faucets, showers, baths and toilets typically consume more than 60% of a home's total potable water use. The installation of high efficiency faucets, toilets and shower heads is a very easy strategy to reduce this indoor water use by consuming less than half of the more conventional fixtures. This credit rewards installation of either high-efficiency or very high efficiency fixtures and fittings in bathrooms.
- To the consumer the high-efficiency fixtures look exactly the same as conventional fixtures.
- Low-flow faucets achieve water savings by the use of aerators , which combine air with water to give the user the feeling that they are getting an equivalent water pressure buy with less water.
- Low-flow showerheads should be installed with proven thermostatic mixing valves that have been designed, tested and verified to function safely at the reduced flow rate.
- Not all high-efficiency toilets operate equally well, and poor design can lean to multiple flushes.
- Some high efficiency toilets have dual flush settings, one for liquid waste and the other for solid waste.
- Use caution when hooking up high efficiency fixtures to gray-water systems as this may void their warranty.
If a project includes multiple fixtures and fittings with different efficiencies, use a straight-line average to determine the overall average efficiency of each fixture type. For example, if tow lavatory faucets have flow rates of 1.5 gpm and a third is rated for 2.1 gpm, the average overall flow rate is equal to (1.5 + 1.5 + 2.1)/3 or 1.7 gallons per minute. For the purposes of this calculation, all dual-flush toilets should be treated as 1.25 gpm, or the high-flow volume, whichever is lower.
Projects which can verify flow rates substantially lower than the requirements for LEED WE 3.2 can earn 1 additional point, to be counted under Innovation & Design 3. The application must be submitted by the Provider and approved by USGBC before the point can be counted.
Trade: Deliver any equipment literature (e.g., user manuals, brochures, specifications) related to fixtures and fittings to the builder or team leader.
Builder/Project Team: Place any literature and other fixture information in the Owner Maintenance Manual.
Green Rater: Visually verify that all fixtures and equipment are installed and in operation.
A project receiving points for LEED WE 1.3 must skip LEED WE 1.1 and LEED WE 1.2.
Rainwater harvesting and graywater reuse irrigation systems should be integrated with resource-efficient landscape LEED SS 2 and irrigation system design LEED WE 2.
