GREEN BUILDINGS COMMITTEE

South Coast AQMD Strengthens Large Water Heater Rule 1146.2

The agency’s new policy will lead to cleaner water heaters across four counties.

June 8, 2024

At its Board meeting on Friday, South Coast Air Quality Management District (South Coast AQMD) enacted new requirements for many types of gas water heaters to meet a zero-emission nitrogen oxide (NOx) standard when replaced. The policy, known as Rule 1146.2, applies to water heaters rated between 75,000 and 2 million Btu/hr. This class of appliances includes small commercial boilers, most pool heaters, large water heaters in multifamily homes, and all tankless water heaters. The rule does not apply to larger commercial boilers or most residential water heaters that use a tank, and does not apply to furnaces of any size.

The South Coast AQMD’s jurisdiction includes 17 million people across parts of Los Angeles, San Bernadino, and Riverside County, and all of Orange County. The agency is responsible for reducing air pollution from stationary sources, and Friday’s action was part of implementing its 2022 Air Quality Management Plan, which is designed to bring the region’s air quality into attainment with federal standards (the region is currently in “extreme” non-attainment"). According to RMI analysis of EPA data, fossil fuel use in buildings release more than nine times more NOx and four times more PM2.5 than all power plants in the region.

According to a South Coast AQMD press release, there are about a million units that are covered by the rule, including about 700,000 residential pool and spa heaters. The rule is expected to reduce about 5.6 tons of NOx emissions per day, which makes it second only to the refineries rule in impact of rules passed in the past 10 years.

A coalition of environmental and environmental justice groups attended the board meeting in Diamond Bar to support the rule (and other important board actions) and to celebrate its passage Friday afternoon. The coalition includes Sierra Club, EarthJustice, RMI, Coalition for Clean Air, Building Decarb Coalition, and more.

The rule has different deadlines for new and existing buildings and based on unit type. Smaller units will be required to be zero-emission in new buildings starting on January 1, 2026, while the requirement doesn’t kick in for existing buildings until 2029. For larger units and pool heaters the deadlines are 2028 for new buildings and 2031 for existing buildings, and for the largest units the deadlines are 2029 and 2033.

In residential units and small businesses, appliances only need to be replaced with zero-emission upon natural replacement, while larger businesses will be required to replace existing equipment when they reach the end of their unit age, as defined in the rule. South Coast AQMD included numerous extension opportunities based on concerns expressed by the business community.

- Michael Rochmes
Chair, Green Buildings Committee

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