Can I Have Gas in My New ADU in Orange County? What California Homeowners Need to Know

If you're planning a new ADU in Orange County or LA County, this question comes up constantly: Can I still use natural gas, or is California forcing me to go all-electric?

The short answer is yes — gas is still an option. But the path to getting there is more complicated than it used to be, and understanding the rules before you design your ADU will save you time, money, and surprises at the permit counter.

What Happened With the Local Gas Bans

For several years, it looked like gas was getting squeezed out of new construction entirely. Starting with Berkeley in 2019, a wave of California cities passed local ordinances — called "all-electric reach codes" — that banned gas in new buildings. Many homeowners assumed they'd have no choice but to go all-electric on any new ADU.

Then the legal landscape shifted. In April 2023, the Ninth Circuit Court of Appeals ruled in California Restaurant Association v. City of Berkeley that Berkeley's gas ban was preempted by federal law — specifically, the Energy Policy and Conservation Act (EPCA) — and struck it down. The court found that cities cannot ban gas appliances indirectly by prohibiting the pipes that supply them. Berkeley ultimately settled and agreed not to enforce its ban.

That ruling was binding across nine western states, including California, and it put the brakes on the patchwork of city-level gas bans that had been spreading. Other municipalities with similar reach codes saw significant legal challenges as a result.

So no, California never passed a blanket statewide mandate forcing new ADUs to be all-electric — and the city-level bans that many homeowners feared were struck down at the federal level.

What California's Title 24 Energy Code Actually Requires

The more relevant framework for your ADU today is California's 2025 Title 24 Energy Code, which applies to any ADU or JADU permitted on or after January 1, 2026. This code doesn't ban gas — but it makes going all-electric the path of least resistance.

Title 24 has two compliance pathways, and which one you use determines whether gas is realistic:

Prescriptive path — The simpler compliance route. For new detached ADUs, heat pump water heaters are the mandatory baseline. Choosing gas on this path is very difficult; the prescriptive requirements are designed around high-efficiency electric systems.

Performance path — The more complex route. Your designer or engineer models the ADU's total energy use and demonstrates it meets the state's overall energy budget. Gas appliances remain allowed here — if your design hits the required efficiency targets across the whole project.

California's 2025 code also replaced the old compliance metric with something called Long-Term System Cost (LSC), which measures 30-year energy costs. All-electric and heat pump systems score well under LSC. Gas systems can still comply, but they require more work on paper to get there.

This is also why whether your ADU is classified as new construction, an addition, or an alteration matters so much — the Title 24 obligations aren't identical across all three. And it ties directly to the solar question: if you're curious about when solar is and isn't required under Title 24 for ADUs and JADUs, that classification is the same starting point.

What This Means Practically if You Want Gas

If your ADU design includes a gas range, gas water heater, gas dryer, or gas furnace, here's what you're looking at:

The performance path for Title 24. Your designer will need to run the energy calculations to demonstrate compliance — this adds cost and time compared to the prescriptive path.

A new gas line. This typically requires its own trench, which increases cost — especially for detached ADUs located far from the main house's existing gas service. Expect additional plan check steps and potentially longer permit timelines in some cities.

Verify your specific city's rules. Not every city is the same. While the Berkeley ruling limited outright gas bans, some local ordinances may still add layers on top of the state framework. Always confirm with your city's building department before assuming what's allowed.

The HCD ADU Handbook sets the state-level baseline — your city applies its own layer on top. California's HCD ADU policy page is the authoritative reference for state law, and your local planning department is the final word on what's permitted in your specific jurisdiction.

Gas vs. All-Electric: What Are You Actually Choosing Between?

If gas is still on the table in your city and you're deciding which way to go, here's the honest comparison:

Gas gives you familiar cooking performance — many people strongly prefer gas ranges for temperature control and cooking feel. Upfront appliance costs are sometimes lower. And if your property already has an existing gas line running close to where the ADU will be, the hookup cost is reduced.

All-electric systems — specifically heat pumps — have become significantly more reliable and affordable, and they move through permitting faster in most California jurisdictions. Heat pump water heaters use up to 70% less energy than traditional gas water heaters. A heat pump HVAC system handles both heating and cooling in a single unit, which matters a lot for a compact ADU. And an all-electric design almost always clears the prescriptive path without the engineering overhead the performance path requires.

For investment ADUs — units you're building to rent — operating cost differences tend to matter less to your underwriting than getting the unit permitted and cash-flowing efficiently. If you're buying a property with an existing ADU, how the unit is configured — including whether it has separate utility metering — is one of the details worth confirming before you remove contingencies. Lenders and future buyers both care about this.

The Bottom Line

Gas is allowed in California ADUs. The state never passed a blanket mandate forcing all-electric, and the city-level bans that tried to get there were overturned at the federal level. What you're navigating is a Title 24 compliance framework that has made gas harder — not impossible — to include, and a local city landscape where rules still vary.

If you want gas appliances in your new ADU, talk to your designer early. The performance path adds complexity and cost, but it's not a wall. High efficiency is the real requirement — gas or electric, California wants your ADU to be a well-performing, energy-conscious unit. That's true regardless of which fuel you choose.

Questions about how utility configuration affects an ADU property's value or rental potential in Orange County or LA County? Reach out directly at (714) 860-2868.