Which Water Efficiency Rating System Works for You?

Green Certifications

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, 2019 Edition found that more than 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? This matrix tool — one of many NAHB Green Resources available to all builders and developers — allows you to quickly evaluate and compare the features and requirements of several above-code water efficiency and conservation programs to assist in your decision-making.

The matrix provides information on applicability, requirements, costs and scope for several programs:

  • 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.
  • 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.

To stay current on the high-performance residential building sector, follow NAHB’s Sustainability and Green Building team on Twitter.

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