Air District Board of Directors adopts water heater rule amendments and delays implementation to January 2028

The amendments delay the compliance date from January 2027 to January 2028. The standard applies only when a property owner replaces an existing water heater. It does not require any household to remove a working appliance, and it does not apply to stoves, dryers or fireplaces.

“Water heaters are a significant source of air pollution in the Bay Area, and cleaner alternatives can help people live longer, healthier lives,” said Dr. Philip Fine, executive officer of the Air District. “With these practical amendments, the Board focuses the rule on the properties that can most easily make the switch and gives relief to households that cannot afford the change without financial assistance.”

“The Board raised real questions about cost and implementation in May. Staff did the work, and the rule we adopted today reflects what we heard,” said Air District Board Chair Lynda Hopkins. “This decision protects public health and respects what households can manage. I thank the residents, contractors and local governments who took part in this process.”

The Air District published the draft amendments on July 14, 2026, a rule proposal package on October 2, 2026, and accepted public comment through the fall.

The amendments establish exemption categories:

• Low-income property owners, defined as those earning less than 80 percent of Area Median Income and including participants in programs such as Medi-Cal or CalFresh; or households paying more than 28 percent of their income toward their mortgage and property taxes.
• Space-constrained properties without enough room or ventilation to install a compliant unit.
• Properties with electrical limitations, such as panels below 100 amps, insufficient panel capacity or a need to run electrical lines more than 50 feet.

The adopted amendments also include allowances for temporary installations for emergency situations and a further delayed compliance date to January 1, 2033, for water heaters installed in multifamily buildings and deed restricted affordable housing as well as certain product categories such as hydronic units, specialized high heat uses, and large water heaters. Water heaters with capacity of 30 gallons or less and mobile home water heaters are not required to comply with the zero-NOx standard.

Rule 9-6 has been in place since 1992, limiting emissions of nitrogen oxides, or NOx, from natural gas-fired water heaters. The Air District amended the rule in 2023 to set a zero-NOx standard. NOx contributes to smog and fine particulate matter, and Air District analysis found that pollution from gas-fired water heaters and furnaces cause as many as 85 premature deaths and 15,000 asthma attacks in the Bay Area each year.

Property owners can find guidance on the compliance timeline, the exemption categories and available rebates on the Air District's Building Appliances web page.

View press release(181 Kb PDF, 2 pgs, posted 11/4/2026).