Home Innovation Insights

Cindy Wasser, MBA
January 15, 2021

WRI — the New “MPG” Metric for Home Water Use

As consumers, we appreciate the opportunity to use performance metrics to estimate the total cost of ownership of our vehicles, homes, and appliances. Since 1977, a miles per gallon (or MPG) metric has been displayed prominently on vehicle labels. Consumers rely on that metric for understanding how much it would cost to operate a vehicle for their daily commute, errands, and social activities. No matter how stylish, roomy, or tech-enabled a vehicle is, I couldn’t imagine purchasing it before researching that MPG value.

When purchasing a home, buyers can look to RESNET’s HERS score and the IECC Energy Rating Index (ERI) to understand how much it would cost to heat and power a particular home. The easy-to-understand, 0-to-100 scales of these rating systems allow buyers to consider both mortgage and energy costs and compare multiple homes during their home search. Now, homebuyers can look for a similar metric that indicates expected total water use of a particular home.

The 2020 NGBS introduced the Water Rating Index (WRI) as a new optional path for newly-constructed homes to demonstrate compliance with water efficiency criteria. Like the HERS and ERI ratings, a WRI score is a value between 0 and 100, and can be used to understand the operational costs of a given property.

A WRI score indicates a property’s total indoor and outdoor water use compared to a baseline derived from the home’s size and configurations. Just like with HERS and ERI, a lower score demonstrates higher efficiency. A WRI score of 70 or below can be used to comply with either the New Construction or Single-Family Certified paths under the 2020 NGBS.

Example WRI Score

Builders who take advantage of this new opportunity can be on the cutting edge of efficiency and will set their homes apart from other green certified homes. Builder benefits include:

  • Ability to use new terminology to communicate expected water use
  • Ability to leverage an additional third-party label as part of your marketing
  • Access to new tools that can help you consider various design choices and their impact on water use and expected NGBS points
  • Opportunity to pursue the NGBS Green+ ZERO WATER badge

To take advantage of this new opportunity, you must select an NGBS Green Verifier who has been accredited for the 2020 NGBS, and who also holds the WRI Verifier credential. These individuals have undergone additional training related to water efficiency and have access to the calculator tools necessary to score and verify a home’s WRI value. We have created a listing page for these individuals – if you don’t see a verifier in your area, talk to your existing NGBS Green Verifier; ask if he/she is pursuing WRI accreditation.

Just getting started with NGBS Green? Consider pursuing a certified WRI score to help buyers understand that your homes are the best green and water efficient choice.

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