A building project boasting a Leadership in Energy and Environmental Design (LEED) certification usually conjures images of an innovative design, a healthier environment, less energy consumption, and lower utility bills. But LEED goes beyond comfort and cost savings to encourage building owners to protect one of the world’s most vital natural resources – water. In order to become LEED certified, a building must achieve at least a 20% reduction in water usage, with additional points available for water efficiency measures implemented both indoors and out.
The LEED certification process evaluates a building’s environmental performance in several categories, including Water Efficiency. What are some strategies available to LEED projects to earn points and achieve water efficiency?
Outdoor Water Use
Building designers, owners, and operators are encouraged to limit the use of potable water resources for landscape irrigation. Potable water is water that meets the Environmental Protection Agency (EPA) standards for drinkable water approved for human consumption. In order to achieve this water conservation goal, the following should be considered:
- Optimal Plant Choices: Regional and site-specific characteristics must be examined to determine which plants are best adapted to the climate and conditions of the project site. Xeriscaping is a technique used to eliminate the need for supplemental irrigation through the use of slow-growing drought tolerant plants and limited amounts of turf grass. Mulch and shrubs may be used in place of thirsty grasses. A review of plant density is helpful to ensure that plants are spaced properly to allow for growth and to achieve a reduction in the amount of plants needed. It is also important to group plants based on irrigation needs.
- Efficient Irrigation: Drip systems and moisture sensors can be used to limit the amount of water consumed by the irrigation system. Moisture sensors with rain shut-offs allow naturally occurring rainfall to fulfill a portion of the irrigation need.
- Recycled Water: Captured rainwater may be used to irrigate. If local codes allow, recycled greywater may also be used to water plants. (Greywater is any untreated water, other than toilet water waste, that is drained from a household.)
Indoor Water Use
- Fixtures: Points are awarded for water savings within a building, beyond the 20% prerequisite reduction, and not counting irrigation. Fixtures considered under the LEED credit include: water closets, urinals, lavatory faucets, showers, and kitchen or break room sinks. The use of water-conserving fixtures, such dual flush or low flow toilets, high efficiency sink faucets, and waterless urinals, can reduce both water demand and the production of wastewater.
- Non-Potable Water: Non-potable water is untreated water that is not meant for human consumption. Use of non-potable water may be an option to supply water for toilet flushing and further reduce potable water demand for sewage. Non-potable water may come from rainwater collection, recycled greywater, and on-site or municipally treated wastewater.
Beyond Water Efficiency
Beyond the Water Efficiency category, LEED also addresses water protections in the Sustainable Sites: Stormwater Design Category. Within this category, points are awarded for measures that control the rate, quantity, and quality of stormwater runoff, to protect receiving bodies of water from erosion and pollution.
Moving Forward with LEED v4
With the expected rollout of LEED Version 4 in 2013, water efficiency credits within the LEED certification point system will be upgraded to further promote the protection of water as a vital resource. Since the EPA estimates that at least 36 states will be facing water shortages by 2013, the updates to the LEED system are timely. Changes include guidelines for water metering, use of the EPA’s WaterSense label program, and cooling tower water use. The changes demonstrate LEED’s ongoing commitment to the conservation and protection of water as part of sustainable building design, operations, and maintenance.
To learn more about green building strategies and the latest version of LEED, check out Everblue’s LEED training courses.
By Amy Malloy