RESNET Officially Adopts Water Efficiency Index

Codewatcher RESNET HERS H20

In February, the RESNET Board of Directors adopted the RESNET HERSH2O.

In many parts of the nation water is fast becoming an ever increasingly expensive commodity. Other parts of the country are experiencing droughts.  There is clearly a need for a system that can mirror the HERS Index to rate a home’s efficiency in water use. This will allow home buyers to know how efficiently water is being used in the homes they are considering to buy. It will also provide an opportunity for homebuilders to monetize the efficiency of their homes in the same fashion that the HERS Index plays for energy efficiency.

By tying HERSH2O with the HERS Index, it will also allow the rapid deployment of the water efficiency rating system through the network of over 1,900 certified RESNET HERS Raters and hundreds of builders that have their homes HERS rated. Technical Guidelines will serve as the technical basis for RESNET’s water efficiency rating system, HERSH2O . The guidelines were developed over a period of more than two years and included a public review and comment process.

The guidelines can be downloaded at RESNET HERSH2O. Technical Guildelines.


The RESNET HERSH2O Technical Guidelines are being field tested by the national production builders KB Home and Meritage Homes in Arizona, California, Colorado, Florida, Nevada, and Texas. The guidelines were featured in an open house demonstration of a KB Home that was HERSH2O rated at the 2018 RESNET Building Performance Conference in Orlando.

RESNET HERSH2O Open House . From left to right:  Jonah Schein, EPA; Jacob Atalla, KB Home; Steve Baden, RESNET; Dave Wall, ICC; Mark Johnson, ICC; Dave Bell, TopBuild; Ed Osann, NRDC.

RESNET is partnering with the International Code Council (ICC) to develop an ANSI national consensus standard for rating the water efficiency rating of a home, the Water Rating Index.  To develop the ANSI candidate standard a joint RESNET/ICC Standard Development Committee (SDC) 1100 was formed.  The SDC 1100 held its first meeting in conjunction with the 2018 RESNET Building Performance Conference.

The initial Water Rating Index standard will be based on the RESNET HERSH2O technical guidelines.

It is expected that the draft Water Rating Index standard will be released soon for public review and comment.