Water Efficiency Certification Programs

Water
Contact: Sustainability and Green Building
sustainability@nahb.org

A checklist with checkmarks and a pen

Certifying your project to an above-code, voluntary water efficiency rating system provides independent confirmation of the water-saving practices you have installed in your projects, and validates to your buyer and the local market that you have built a house to a higher standard than what code requires. The What Home Buyers Really Want, 2021 Edition found that about half of buyers are willing to pay at least $500 for a water efficiency certification, providing an opportunity to stand out in your market.

Water efficient residential design may already be part of your business model; the 2020 Green SmartMarket Brief found that 67% of all single-family builders are using water efficiency practices on at least some of their projects, while 36% are using them on at least 75% of their projects.

Examples of how builders are incorporating these practices include water-conserving fixtures — such as high-efficiency toilets, faucets and showerheads — that were rated as essential or desirable by more than half of the What Home Buyers Really Want respondents. Or it may be something they are incorporating into designs to respond to changing conditions in their market — such as long-term droughts, limited infrastructure or water quality issues — so that they can continue to build.

Which rating system is the best for you as you explore ways to differentiate yourself in the market?

  • NGBS: The ICC 700 – National Green Building Standard® (NGBS) has long recognized and rewarded builders’ efforts to implement water conservation and efficiency practices. New to the 2020 edition is a performance path index that provides a score based on the expected water use (indoor, outdoor and reuse) of the home. (See Certified Water Rating Index (WRI) for an optional water certification path outside of full NGBS certification.)
  • Certified Water Rating Index (WRI): The 2020 NGBS introduced the WRI as a new optional path for newly constructed homes to demonstrate compliance with water efficiency criteria. A WRI score, valued between 0-100, indicates a property’s total indoor and outdoor water use compared to a baseline based on the home’s size and basic configurations. A lower score demonstrates higher efficiency, and a score of 70 or lower can be used to comply with either New Construction or Single-Family Certified paths under the 2020 NGBS.
  • WaterSense: EPA’s WaterSense program, founded in 2006, provides a voluntary path for home certification using certified high-efficiency products. WaterSense has high brand recognition — 21% of those surveyed in the What Home Buyers Really Want, 2019 Edition, were familiar with the program.
  • WERS: The Water Efficiency Rating Score (WERS) originated in the Southwest, where water scarcity threatens to limit residential building in some jurisdictions. Outdoor water use is generally a higher percentage of overall use in this region. Efficient outdoor use and water reuse are recognized in the program along with indoor use.
  • HERSH2O: RESNET recently has launched HERSH2O, a water efficiency program that complements its HERS Index Score for energy efficiency and provides a relative efficiency of the home as compared to a baseline.

Check out the resources below for more information.

Resources