Energy-efficiency is quickly becoming the new standard in home building, but so far, water conservation has lagged behind.

The Water Efficiency Rating (WER) Index, being developed by RESNET to complement its Home Energy Rating System (HERS) Index, hopes to change all that by bringing more attention to—and measurement of—water efficiency in homes.

“The idea is to generate a standard by which we can evaluate the water efficiency of a home in the same way we do energy,” says Steven Baden, RESNET executive director. “Because a green home is not just energy; it has to now include water.”

The need for a WER Index has been driven home by the increasing scarcity of water in some regions due to prolonged drought.  “In some areas, water is getting more expensive than energy,” he adds.

Like the HERS Index, the WER Index will provide a numerical score to represent the home’s performance, with a baseline score of 100. Lower scores indicate a more efficient home.

Since the HERS Index was recently updated to include the measurement of a home’s hot water consumption, a water-efficiency scale was the natural next step, Baden says. The new standard will now develop methods to account for a home’s cold water consumption and outdoor water use.
Marketing and Educational Advantages
With awareness of the importance of water conservation rising, demand for water-efficient homes will continue to grow, Baden says. As interest increases, offering a home’s WER score will serve as a differentiator for builders as well as a benefit for green building programs.

“This would give another tool for builders to market to consumers in terms of high-performance homes: not only the energy benefits, but also the water benefits. Then it becomes a matrix that water districts and other entities could use in providing rebates or [incentives] for water efficiency based upon a whole-house analysis,” Baden explains.

RESNET is actively working with many builders on the initiative. So far, response has been positive, he says. “This was actually driven by their idea of having a metric to be able to monetize their water efficiency. A lot of homes being built now are more water-efficient … but there’s no way that they can show that.”

As water-saving technology continues to improve, more homes are including high-performance fixtures and appliances, or experimenting with drip irrigation or greywater recycling. A WER score would reward builders who are taking advantage of those technologies, Baden says. “Many times in the energy world, builders are largely reactive … this is a real opportunity for builders to position themselves in the lead and actually drive the market.”

Providing a WER score will also help educate consumers about the importance of water conservation in the home and improve understanding of their own household’s water efficiency.

Building on Experience
Leading the effort is an executive committee of Jacob Atalla, vice president, sustainability at KB Home; Ed Osann, senior policy analyst with the Natural Resources Defense Council’s Water Program; and Jonah Schein, technical coordinator for homes and buildings, EPA WaterSense Program. An advisory group representing various water efficiency experts, homebuilders, and environmental groups is also helping develop the index, which is in the process of being drafted using an ANSI consensus standard development process.

Though the initiative has received a positive response, securing builder buy-in and coordinating the logistics to implement new standards can be a challenge. Here, RESNET has an advantage due to its pre-existing infrastructure of HERS raters, who would be able to produce both HERS and WER scores through one home efficiency audit.

“This creates a seamless path to also start including water efficiency in the dialog in terms of selling a home,” Baden says. “Since the rater is in the home already, this would not significantly increase the cost for a builder to also get a water efficiency rating.”

With HERS already growing in popularity—over 1.5 million homes have been rated so far, and one-third of the new homes sold last year received a score—RESNET is ready to build on that momentum.