Bay Area Gas Water Heater Rule Delayed to 2028: Marin & Sonoma Guide

On November 4, 2026, the Bay Area Air District voted to delay its zero-NOx rule for home gas water heaters by one year, from 2027 to January 1, 2028. If you live in Marin or southern Sonoma County and have been wondering whether you need to replace your gas water heater before New Year's, the short answer is no. If you want a straight read on your own setup, call or text Local Plumbing at (415) 234-0370.

Here is what the Board actually changed, what it didn't, and how we're advising homeowners now. For the full background on the rule, see our Air District water heater rule guide.

What Changed on November 4

The Air District Board amended Rule 9-6, the regulation that sets emission limits for gas water heaters and boilers. Two dates moved:

• Gas tank water heaters (over 30 gallons, up to 75,000 BTU/hr): the typical home tank in a garage or closet. The zero-NOx requirement now applies to units manufactured after January 1, 2028. The old date was January 1, 2027.
• Boilers and larger water heaters (over 75,000 up to 2,000,000 BTU/hr), including tankless units: the date moved from January 1, 2031 to January 1, 2033.

The key words are "manufactured after." The rule is tied to the date a unit was built, and it applies when a water heater is sold or installed. In practice, that means a standard gas tank can still be installed in your home through all of 2027.

Source: Bay Area Air District news release, Nov 4, 2026.

What the Rule Does Not Do

There's a lot of confusion out there, so it's worth being clear:

• Nobody has to remove a working gas water heater. The rule only applies when a water heater is replaced. Repairs are still allowed.
• There's no inspection coming to your house. It's a rule about what can be sold and installed, not a retrofit mandate.
• Small tanks of 30 gallons or less are not subject to the zero-NOx requirement.
• Mobile-home water heaters are not subject to it either.
• It doesn't cover gas stoves, dryers or fireplaces.

Gas furnaces fall under a separate rule (Rule 9-4) with a January 1, 2029 date. That date was not changed in this vote.

Exemptions: How They Work

The amendments also create an exemption certificate system. The important part: you need the certificate from the Air District before a gas water heater is installed, not after. The main categories are:

• Income-based: owners who are enrolled in a listed assistance program (such as CARE, FERA or CalFresh) or at or below 80% of area median income, and owners whose mortgage plus property tax is 28% or more of household income. These are self-certified.
• Space and ventilation: for example, an existing gas water heater in an enclosed space under 700 cubic feet that can't be opened up to a larger space, or a garage ceiling under 7.2 feet. One time per address, existing buildings only.
• Electrical: for example, a panel under 100 amps, a panel with no open breaker space, or a new 240V circuit that would need more than 50 feet of conduit. A licensed contractor has to certify this one. Also one time per address, existing buildings only.
• Hydronic water heaters, multifamily buildings of 5+ units, and deed-restricted affordable housing: gas units manufactured before January 1, 2033 can be installed with a certificate.

A few things to know before you count on any of these:

• The certificate website isn't live yet. The Air District says the one-year delay gives it time to build the system.
• Fees aren't set. Staff expect a processing fee for the space and electrical exemptions, with details going to the Board in early 2027.
• The Air District decides who qualifies, not us. We can measure your space and check your panel, and we'll tell you honestly whether you look like a fit. But we can't promise anyone an exemption.

What If Your Water Heater Dies After 2027?

This is the question that worries people most: a tank fails on a cold morning in 2028 and there's no time to plan a heat pump conversion.

The amended rule covers this. A licensed contractor can install a temporary gas replacement for up to 12 months when a compliant unit can't be installed right away. The contractor gets the certificate before the install, and within 12 months the temporary unit has to be replaced with a compliant one or qualify under another exemption. So no one should be left without hot water, but it's a bridge, not a permanent fix.

Northern Sonoma County: A Different Air District

Rule 9-6 is a Bay Area Air District rule. All of Marin is in the Bay Area district, but only the southern portion of Sonoma County is.

• Under the rule: Petaluma, Santa Rosa, Rohnert Park, Cotati, Penngrove, Sonoma, Glen Ellen, Kenwood, Graton and Bloomfield.
• Outside the Bay Area district (Northern Sonoma County Air Pollution Control District): Healdsburg, Cloverdale, Geyserville, Guerneville, Forestville, Monte Rio, Jenner, Bodega Bay and the rest of the coast.
• Split by address: Windsor, Sebastopol, Occidental and Valley Ford. If you're in one of these, check your address on Sonoma County's air district page or ask us and we'll look it up with you.

What to Do Now

You have more time than you thought, and that's the main thing to use. The options look like this:

Replace gas with gas through 2027

If your tank is 10–12+ years old, leaking at the base, or rumbling, and your home isn't ready for electric, a new gas tank is still a straightforward replacement. A gas tank replacement typically runs $3,500–$6,500 installed. See our tank water heater page for what's included.

Go heat pump on your schedule

A heat pump water heater is the long-term direction under this rule. They need more room, airflow, a condensate drain and usually a 240V circuit, which is where Marin homes get tricky: under-stair closets in Gerstle Park, low garages in Terra Linda, older panels in Mill Valley and San Anselmo. A planned conversion typically runs $6,500–$12,000 before rebates. Learn more on our heat pump water heater page.

Consider gas tankless

Gas tankless water heaters are in the larger equipment class, which now has until 2033. Tankless installs typically run $4,800–$6,900, depending on venting, gas line sizing and location. Check the input rating on the unit's rating plate, since the class is set by BTU/hr.

Plan ahead, don't wait for a failure

Emergency replacements cost more and limit your choices. The best move for most homeowners is a quick assessment now: age and condition of your current unit, panel capacity, space and venting. Then you know what goes in when the time comes, instead of deciding on a cold morning. Our local pages cover this in more detail: water heater replacement in San Rafael and water heater replacement in Mill Valley.

Rebates

Rebates have changed a lot in the past year, so be careful with older articles:

• MCE (Marin): MCE currently offers up to $3,000 ($5,000 for ultra-low-GWP models) when a participating contractor installs a heat pump water heater. Amounts and requirements change, so we confirm the current program before you buy.
• Sonoma Clean Power: SCP has its own heat pump water heater program for its customers. Check the current program terms on SCP's site before you count on it.

The federal tax credit for heat pump water heaters ended with installs after 2025, and several statewide programs are fully reserved, so don't plan a budget around them.

Bay Area Water Heater Rule FAQs

Is the Bay Area gas water heater ban still happening in 2027?

No. On November 4, 2026, the Air District moved the date to January 1, 2028, for gas tank water heaters manufactured after that date. Gas tanks can still be installed through 2027.

Do I have to replace my working gas water heater?

No. The rule only applies when a water heater is sold or installed. You can keep using and repairing your existing unit.

Does the rule apply to tankless water heaters and boilers?

Yes, but later. Units over 75,000 BTU/hr, including boilers and tankless water heaters, now have a January 1, 2033 date.

What happens if my water heater fails in 2028?

A licensed contractor can install a temporary gas replacement for up to 12 months while a compliant unit is arranged, with an exemption certificate obtained before the install.

Does the rule apply in Healdsburg?

No. Healdsburg, Cloverdale, Geyserville, Guerneville and the Sonoma coast are in the Northern Sonoma County air district. Windsor, Sebastopol, Occidental and Valley Ford depend on the exact address.

Can I get an exemption to install a new gas tank after 2027?

Possibly, if you qualify on income, housing cost, space or electrical grounds. The Air District decides, the certificate must come before the install, and the application system isn't open yet.

Water Heater Help Across Marin and Sonoma

Local Plumbing installs gas, tankless and heat pump water heaters across Marin and Sonoma counties, from our warehouse and training facility in San Rafael. We're a licensed C-16 and C-36 contractor (Lic #1091739), and we'll give you honest advice about whether to replace now, plan for later, or leave a good unit alone.

Want to know where your water heater stands? Call or text (415) 234-0370, or contact us to book an assessment.