Water Rating Index Added to 2018 NGBS Draft

This water efficiency tool will benefit water-efficient builders and water-conscious communities.

The Consensus Committee developing the next version of the National Green Building Standard (NGBS) approved the Water Rating Index (WRI), as recommended by the Water Task Group. The WRI will go out for public comment as part of the draft NGBS. If approved, the National Green Building Standard will include the WRI methodology as an appendix and will use the WRI as one option for meeting the water efficiency requirements of the NGBS.

“The zero to 100 rating system, patterned after the Energy Rating Index (ERI) already in code, is a simple metric that consumers and water planners can understand and something builders will use to differentiate themselves from competition. It will drive greater efficiency in water conservation just as the ERI has for energy conservation”, said Kim Shanahan, Executive Officer of the Santa Fe Area Home Builders Association.

“In many areas, water is becoming the new energy,” said Craig Conner, founder of Building Quality. “The WRI is a single number representing the water efficiency of a home, including both the inside and outside water use. I expect the WRI to be used where water availability is limiting construction. The WRI can also be used to compare the costs of achieving water efficiency in homes with the cost of expanding the water supply infrastructure. In many cases, new-home water efficiency will be much less expensive than expanding the water supply and treatment infrastructure.”

The WRI proposal passed overwhelmingly, receiving a 90% majority approval from the Committee. It calls for the creation of an alternative compliance path, whereby builders receive credit for four levels of achievement in the water efficiency chapter depending on the outcome of their water rating. On a scale of 0-100, where lower is better, the following table was approved:

WRI NGBS Level
70 Bronze
60 Silver
50 Gold
40 Emerald

 

This is great news for both water-efficient builders and water-conscious communities. Builders who use the NGBS would be able to get the credit they deserve for their water-efficient practices, and municipalities that need to ensure their water future would have an ANSI standard to employ.

Mike Collignon is Executive Director of the Green Builder Coalition and Chair of the WERS Development Group