According to the United Nations, water scarcity affects more than 40% of the global population, and the Environmental Protection Agency estimates that 40 U.S. states will have water shortages by 2024. Access to clean water is necessary for human beings to maintain their health and food supply, but pollution, drought and waste challenge resources worldwide—in ways that will only increase.
Joining the struggle to provide adequate water for all people, USGBC hosted the WaterBuild Summit for three years running, bringing together professionals from around the world to focus on solutions to water issues. In 2019, we launched the Living Standard campaign, which promotes the right of all people to health, safety and well-being. LEED v4.1, the latest version of the LEED rating system, also addresses these issues by setting a high standard for responsible use of water.
Conserving water is not optional
The LEED rating system encourages water use reduction, rainwater management and the employment of alternative, nonpotable water sources for appropriate end uses. In addition, it goes to the heart of the root causes—climate changes making water scarcity worse—with a focus on overall carbon reduction.
In LEED v4.1 for Building Design and Construction (BD+C), Outdoor Water Use Reduction, Indoor Water Use Reduction and Building-level Water Metering are required prerequisites for achieving Water Efficiency (WE) credits.
Here are some examples of how effective water management is outlined in LEED v4.1 for BD+C:
The Water Efficiency category in LEED v4.1
The WE prerequisites and credits in LEED v4.1 BD+C include the following priorities:
- Installation of permanent water meters that measure the total potable water use for the project; teams are also encouraged to submeter water subsystems.
- Irrigation of outdoor spaces must be shown to either be unnecessary or to be reduced by at least 30% from typical figures, through the selection of native or adapted plants for landscaping, alternative water sources for irrigation or irrigation efficiency measures.
- Using appliances with certain efficiency standards is mandatory, as is the installation of WaterSense-certified, low-flow fixtures, to reduce indoor water use.
- A new option in the former Cooling Tower Water Use credit addresses water used for mechanical processes. This credit encourages the recycling and reuse of nonpotable water for cooling and mechanical building needs.
The Rainwater Management credit in LEED v4.1
The Sustainable Sites category's Rainwater Management credit in LEED v4.1 BD+C encourages projects to mitigate the problems of stormwater runoff pollution by responsibly managing rainwater on-site.
- Rain gardens, vegetated roofs, permeable paving and water collection features, such as cisterns, can be employed to contain at least 80% of the water from regional or local rain events.
- Projects with a zero lot line must treat runoff from impervious surfaces to reduce the likelihood of pollutants entering into local waterways.
- View the LEED v4.1 BD+C rating system with changes tracked.
- Take courses in water efficiency on Education @USGBC.
- Review USGBC's report covering water management in green buildings in California.
- Read in USGBC+ how Green Building Council South Africa dealt with a water crisis.
- Explore LEED Zero and how you can gain recognition for net zero water use.