Utah Lessens Statewide Ultra-low NOx Emission Mandate to Nonattainment Areas

During the Utah 2025 General Legislative Session, the State Legislature passed HB 313, which directed the Utah Air Quality Board to amend Utah State Code to limit the ultra-low nitrogen oxide (NOx) emission limits for natural gas water heaters from a statewide mandate to only apply in ozone and PM2.5 nonattainment areas in Utah. See the image below for the nonattainment areas that will continue to follow the ultra-low NOx requirement for water heaters.

When does the change go into effect?

On May 7, the Utah Air Quality Board officially proposed the amendments passed by HB 313’s adopted by the state legislature. Then, on August 6, the Utah Air Quality Board formally adopted the ultra-low NOx emission limits for nonattainment areas, which immediately went into effect upon adoption. These nonattainment areas are generally located along the Wasatch Front and in the Uinta Basin, but do not follow city, county, ZIP Code, or other typical geographic boundaries. You can generally view the nonattainment areas above.

How to help you and your customers stay compliant

HARDI recommends that members use the Utah Air Quality Board web tool to help contractors stay aware of whether they are selling and installing a noncompliant water heater to a home or business owner.

If you have any questions, contact HARDI’s Director of State and Public Affairs, Todd Titus.

Relevant Resources

Court Rules that EPCA Does Not Apply to California Zero-NOx Emission Regulation