Plumbing guide · San Jose, CA
The 2027 Bay Area water heater rule, explained for San Jose homes
Starting in 2027, the gas tank water heater most San Jose garages have had for decades stops being an option for new installs. Nothing has to be ripped out early, but the next replacement will look different, and planning for it before the old tank fails saves money and a cold week.
By Earl Newcomb, Plumbing Guides Editor · Updated September 2026
Under Bay Area air district rules adopted in 2023, from January 1, 2027 new storage water heaters under 75,000 BTU per hour sold or installed in the Bay Area must be zero-NOx, which in practice means electric models such as heat pump water heaters. Existing gas water heaters can keep running until they need replacing; the rule applies to the next one you buy.
What the rule actually says
The Bay Area Air Quality Management District adopted amendments to its appliance rules in March 2023 that set zero-NOx emission standards for new appliances. For residential storage water heaters under 75,000 BTU per hour, the standard takes effect on January 1, 2027. Furnaces follow in 2029, and larger water heaters, including many units rated above that size, in 2031.
Zero-NOx means the appliance produces no nitrogen oxide emissions at the unit, and today the practical way to meet that is an electric water heater. For most San Jose homes, that means a heat pump water heater, which moves heat from the surrounding air into the tank and uses far less electricity than a standard electric-resistance tank.
What it does not do
The rule does not require anyone to replace a working gas water heater. It applies to sales and installations from the effective date, so a gas tank installed before 2027 can stay until it wears out. It also does not touch gas ranges, dryers or fireplaces. Rules can be adjusted before they take effect, so check the air district's current version before making a purchase decision based on a date.
Ready when you are
Old gas tank and 2027 coming?
Call any hour. We can check your space and panel before the tank fails.
Why planning ahead matters
Most water heaters are replaced in a hurry, when the old one leaks or stops heating. A heat pump water heater is a different install from a like-for-like gas swap: it needs a dedicated 240-volt circuit in most cases, room around the unit for air, a condensate drain, and sometimes a panel upgrade. Doing that work in an emergency is slower and more expensive than planning it.
If your gas tank is more than about ten years old, it is worth checking now whether the garage or closet has the space, whether the electrical panel has room, and where the condensate line would go. Our heat pump water heater installation page covers what that visit looks like.
What happens to the gas line
When a gas water heater is replaced with an electric one, the gas branch that fed it should be capped properly, not left on a closed valve. The old flue opening also needs closing by a sheet-metal or roofing contractor. If you are taking other appliances electric at the same time, it can make sense to retire several branches at once; see gas line capping.
Costs and rebates
A heat pump water heater costs more up front than a gas tank, and the electrical work adds to it, but operating costs are typically lower, and rebates from local energy programs and federal tax credits have often offset part of the cost. Programs change, so check current offers before buying, and keep the receipts and model numbers your installer gives you.
Cost figures on this page are planning ranges from published guides, not quotes: plumbingpriceguide.com (2026); proplumbersanjose.com (2026-07-26). Every job is priced after we see it.
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Where this guide leads
More guides: What ADU plumbing takes, SB 407 and water-conserving fixtures, Sewer lateral replacement cost.
FAQ
Questions readers ask
No. The rule applies to new installs; a working gas heater can stay until it fails.
Units above 75,000 BTU per hour fall under the later 2031 standard.
For most homes, a heat pump water heater.
Most need a dedicated 240-volt circuit.
Yes; the standard applies from January 1, 2027.
Planning your next water heater?
Call any hour; a dispatcher answers and books a look at your space.
Updated September 2026