Research study
The cities where your ADU cannot have gas
A question with a clean answer in 2022 and a genuinely unsettled one now. We report the mechanism and the ruling, and we do not publish a city list we could not verify.
Written by HyreADU Research Desk Primary-source research and data analysis
Audited by HyreADU Research Desk Citation and retrieval-date audit
The finding
California cities can go beyond the state energy code, and the mechanism is a single statutory clause. Public Resources Code section 25402.1(h)(2) permits enforcement of local “energy conservation or energy insulation standards” beyond the state minimum, provided the city files its cost-effectiveness determination with the Energy Commission and the Commission finds the standards will cut energy use below the state minimum.
That filing-and-finding requirement is what a “reach code” is. But federal law took a large bite out of one popular design for those ordinances. In California Restaurant Association v. City of Berkeley, the Ninth Circuit held: “Based on its text, structure, and context, we conclude EPCA preempts building codes like Berkeley’s Ordinance that ban natural gas piping within new buildings.” The opinion was filed 17 April 2023, amended on 2 January 2024, and rehearing en banc was denied.
Meanwhile the statewide code already does much of what people imagine a reach code does. Since the 2022 Energy Code took effect on 1 January 2023, a newly constructed single-family building — which includes a new detached ADU — that installs gas or propane space heating, water heating, cooking or clothes drying must carry the dedicated 240-volt circuits and reserved panel space to replace each of them electrically later.
Whether any of this reaches your ADU depends first on a classification. The Energy Code treats most ADUs as additions rather than newly constructed buildings, and the Commission states that “[t]here are no electric ready requirements for additions or alterations.” What this edition does not contain is a list of cities, and that is deliberate. The Energy Commission’s local-ordinance pages returned HTTP 404 on this date.
Publishing a 2022-vintage city list after a federal preemption ruling would be actively misleading, so we publish the mechanism and say what we could not get. Not legal advice.
Read this first
- We publish no jurisdiction list, and you should be wary of ones that have not been re-dated since 2023
This is the single most important thing on the page. Reach-code rosters circulated widely between 2019 and 2022 and are still being reproduced.
Between then and now a federal appellate court held that EPCA preempts building codes banning gas piping in new construction, and jurisdictions responded in different ways at different times. A list without a per-jurisdiction retrieval date is not evidence of anything in 2026. We could not retrieve a current one, so we publish none.
- This is not legal advice and we reach no preemption conclusion about any named ordinance
The Ninth Circuit itself framed its holding narrowly — “[o]ur holding here is limited. We conclude only that EPCA applies to building codes and that Berkeley’s Ordinance falls with[in] the Act’s preemptive scope.” Preemption analysis turns on the specific text of the specific ordinance.
Whether a particular city’s current ordinance is preempted is a legal question about that ordinance, and answering it is a lawyer’s job. We quote the holding; we do not extend it.
- A reach code is not the only way a fuel decision gets made for you
Gas service availability, the cost of extending a gas line to a detached unit, an existing meter’s capacity, and the statewide electric-ready mandate can all settle the question before any ordinance does. In practice many ADU projects go all-electric for reasons that have nothing to do with policy.
- Nothing here is instruction for gas or electrical work
Gas piping, appliance connection and electrical service work in California is licensed work under permit — a C-36 plumbing contractor for gas piping, a C-10 electrical contractor for electrical.
This page describes what codes require. It does not describe how to do anything, and an unpurged or untested gas line is not an area for improvisation.
What a reach code actually is
A “reach code” is not a free-standing power. It is the exercise of a narrow permission in the Public Resources Code, and the permission has procedural strings attached.
Section 25402.1(h)(2) allows enforcement of local energy standards on buildings “on which actual site preparation and construction have not commenced before the effective date” of the state standards, but only “if the city or county files the basis of its determination that the standards are cost effective with the commission and the commission finds that the standards will require the diminution of energy consumption levels permitted by” the state rules.
Two conditions, then: the local government must file a cost-effectiveness determination, and the Energy Commission must find that the ordinance actually reduces energy consumption below what the state code permits.
A cost-effectiveness determination remains valid for a defined period unless circumstances substantially change. The section as retrieved was amended by AB 1533 (Stats. 2024, Ch. 353), effective 1 January 2025.
The Commission itself describes the practice approvingly, in its own 2022 standards summary: “after each update, many cities and counties choose to adopt standards that exceed the state minimum … Reach standards are an important tool for jurisdictions to meet their own climate goals … Historically, such local ordinances have served as a bellwether for statewide standards.”
HyreADU analysis: the filing requirement is the reason a reach code is, in principle, a knowable and enumerable thing — the ordinances are filed with a state agency.
It is also why the absence of a retrievable current list is a genuine research failure rather than an inherent limitation of the topic. The list exists. We could not reach it on this date.
The ruling that reshaped the landscape
Every date below is taken from the face of the amended opinion, retrieved as a PDF from the Ninth Circuit’s own document store on 2026-09-05.
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21 November 2019
The California Restaurant Association sues BerkeleyFiled in the Northern District of California, D.C. No. 4:19-cv-07668-YGR, before District Judge Yvonne Gonzalez Rogers. The challenged ordinance prohibited “the installation of natural gas piping within newly constructed buildings.” The panel later described the Association, “whose members include restaurateurs and chefs,” as having Article III associational standing.
-
District court
The suit is dismissed on a narrow reading of EPCAThe panel later characterized the ruling this way: “in dismissing the suit, the district court limited EPCA’s preemptive scope to ordinances that facially or directly regulate covered appliances, but such limits do not appear in EPCA’s text.”
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12 May 2022
Argued and submitted in San FranciscoBefore Circuit Judges Diarmuid F. O’Scannlain and Patrick J. Bumatay, and Judge M. Miller Baker of the United States Court of International Trade, sitting by designation.
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17 April 2023
Opinion filed: EPCA preemptsOpinion by Judge Bumatay, with concurrences by Judge O’Scannlain and Judge Baker.
The court: “EPCA’s preemption provision extends to regulations that address the products themselves and building codes that concern their use of natural gas … EPCA thus preempts Berkeley’s building code, which prohibits natural gas piping in new construction buildings from the point of delivery at the gas meter.”
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2 January 2024
Amended opinion; rehearing en banc denied; no future petitions entertainedThe panel “issued (1) an order amending its opinion … denying a petition for rehearing en banc; and ordering that no future petitions will be entertained; and (2) an amended opinion reversing the district court’s dismissal.” Judge Friedland dissented from the denial of rehearing en banc; Judge Berzon filed a statement respecting the denial.
The existence of a dissent from denial and a separate statement is itself a signal that the question was contested within the court.
Four shapes an all-electric ordinance can take
A taxonomy from the HyreADU Research Desk, offered so that you can read your own city’s ordinance and see which kind it is. The right-hand column is HyreADU analysis, not a legal conclusion about any ordinance, and it is not advice. Preemption turns on the specific text.
| Ordinance shape | What it does to a new ADU | What the Ninth Circuit actually addressed | HyreADU reading — treat as analysis, not advice |
|---|---|---|---|
| Prohibits natural gas piping in new construction | No gas line to the unit at all; every end use is electric by necessity. | This is the shape the court held preempted. “EPCA preempts building codes like Berkeley’s Ordinance that ban natural gas piping within new buildings.” | Squarely within the holding as written. Whether a particular ordinance of this shape remains in force is a question for that jurisdiction, and we name none. |
| Sets an energy-budget or performance target the design must meet | A gas design must compensate elsewhere in the envelope or systems to hit the target. | Not addressed. The court said “[o]ur holding here is limited.” | A different mechanism, and one EPCA § 6297(f)(3) contemplates by setting seven conditions a State or local building code addressing energy efficiency must satisfy — including that “[t]he code does not require that the covered product have an energy efficiency exceeding the applicable energy conservation standard.” Whether any given ordinance satisfies those seven conditions is a legal question. |
| Requires electric readiness while permitting gas appliances | Gas is allowed, but the circuits and panel space for future electric replacements must be installed. | Not addressed. | This is now the statewide baseline for newly constructed buildings under the 2022 Energy Code, so an ordinance of this shape adds nothing for a new detached ADU unless it goes further — for example by reaching additions and alterations, which the state mandate expressly does not. |
| Requires EV charging capacity, panel capacity or wiring readiness | Affects the service size and panel specification rather than the fuel choice. | Not addressed. | A different regulatory subject from appliance energy use. See our electrical service study for what panel and circuit obligations do to a project budget. |
Taxonomy and right-hand column: HyreADU Research Desk. Quoted holding: California Restaurant Association v. City of Berkeley, No. 21-16278 (9th Cir.), amended opinion of 2 January 2024. EPCA conditions: 42 U.S.C. § 6297(f)(3), retrieved 2026-09-05.
Where we stop. We are not telling you that any ordinance is valid or invalid, and we name no city in this table on purpose.
What we are giving you is a way to read your own ordinance and ask a better question of your planning department: which of these four things does this ordinance do, and does the department currently enforce it?
What the statewide code already requires, with no reach code at all
Before you go looking for a local ordinance, note how much of the “all-electric” agenda the state code already carries.
These are mandatory measures for a newly constructed single-family building — which includes a newly built detached ADU — with no trade-off available: the Commission states “[t]here are no performance or prescriptive electric ready requirements for single family buildings.”
| If the ADU installs this gas appliance | The 2022 Energy Code requires | Applies to an ADU classified as an addition? |
|---|---|---|
| Gas cooktop or range | 240 V dedicated circuit, minimum 50 amps, within 3 feet, plus a reserved double-pole breaker space labeled “Future 240V Use”. Not required for a stand-alone gas oven. | No — “There are no electric ready requirements for additions or alterations.” |
| Gas furnace | 240 V dedicated circuit, minimum 30 amps, within 3 feet, blank cover identified as “240V ready”, plus reserved double-pole panel space. | No |
| Gas or propane water heater | A designated 2.5 ft × 2.5 ft × 7 ft space for a future heat-pump water heater, a condensate drain, a 125 V 20 A receptacle on a 10 AWG three-conductor circuit (or a 240 V 30 A circuit if the designated space is more than 3 feet away), and reserved panel space. | No |
| Gas clothes dryer (where gas piping to serve one is installed) | 240 V dedicated circuit, minimum 30 amps, within 3 feet and accessible, plus reserved double-pole panel space. | No |
| Outdoor grill, barbecue pit, fireplace, stand-alone oven | Nothing. “Any gas appliances not listed … are not required to meet the mandatory electric ready requirements.” | Not applicable |
| No gas appliances at all | Nothing — the requirements “are not applicable when electric equipment is installed.” | Not applicable |
Quoted from the California Energy Commission’s 2022 Single-Family Residential Compliance Manual (CEC-400-2022-006, May 2022), chapter 10, “Electric Ready Requirements”, retrieved and text-extracted 2026-09-05. The 2022 Energy Code took effect 1 January 2023; the 2025 Energy Code applies to permit applications submitted on or after 1 January 2026 and we could not retrieve its manual.
HyreADU analysis. Read this table alongside the preemption ruling and a pattern emerges.
The provisions most exposed to the EPCA argument are the ones that forbid a fuel; the provisions that survive most comfortably are the ones that require readiness for a future fuel.
California’s statewide code is already built on the second design. Whatever happens to local gas bans, the direction of the state baseline is not in doubt.
What this means for an ADU specifically
First establish whether your unit is even in scope
The Energy Commission classifies most ADUs as additions, not newly constructed buildings: every conversion of existing unconditioned space, attached or detached; a newly built unit attached to the house; a newly built unit “on top of existing detached garage or side-by-side with existing detached garage”; and a JADU.
Only a detached, newly built structure — or one joined to the house solely “by breezeway, or covered walkway” — is a newly constructed building.
That classification is the Energy Code’s. A local reach code writes its own scope, and some reach beyond new construction into alterations and additions. Read the ordinance’s applicability section first, not its requirements section.
Extending gas to a detached unit is often the real constraint
Independently of any ordinance, running gas to a detached ADU means a new line, a trench, and — depending on the utility — a meter or a manifold arrangement. That cost frequently exceeds the appliance cost difference on its own.
Our utility connection study sets out what a permitting agency may and may not charge for a connection, and notes that Government Code section 66313(k) puts utilities and special districts inside the statutory definition of a permitting agency. It also records a tension we could not resolve between the statute and one filed electric tariff.
An all-electric ADU changes the electrical brief, not just the appliance list
A heat pump, a heat-pump water heater and an induction cooktop are real connected load, and they land in the load calculation that decides whether the property’s service needs upgrading.
That is a question for a licensed C-10 electrical contractor or an electrical engineer, on your specific existing service, and it should be commissioned before the drawings are finished rather than after.
The counterintuitive point, developed in our service upgrade study: choosing gas in a newly constructed ADU does not necessarily save panel space, because the electric-ready mandate makes you reserve it anyway.
How to ask the question at the counter
Three questions, in writing. One: does this jurisdiction have a locally adopted energy ordinance filed with the Energy Commission under Public Resources Code section 25402.1(h)(2), and what is its ordinance number and adoption date?
Two: does it apply to an accessory dwelling unit, and does it apply to additions and alterations or only to new construction? Three: is the department currently enforcing it, and has its position changed since January 2024?
The third question is the one worth asking explicitly. It is not a trick question and planning staff will not be surprised by it.
The terms, precisely
- Reach code
- Not a statutory term. The practice is authorized by Public Resources Code section 25402.1(h)(2), which permits enforcement of local energy standards where “the city or county files the basis of its determination that the standards are cost effective with the commission and the commission finds that the standards will require the diminution of energy consumption levels permitted by” the state standards. Section retrieved 2026-09-05; amended by Stats. 2024, Ch. 353 (AB 1533), effective 1 January 2025.
- EPCA
- The federal Energy Policy and Conservation Act. Its preemption clause, 42 U.S.C. § 6297(c), provides that once a federal energy conservation standard becomes effective for a covered product, “no State regulation concerning the energy efficiency, energy use, or water use of such covered product shall be effective with respect to such product” unless it meets listed exceptions. Retrieved from the Legal Information Institute 2026-09-05.
- Covered product
- A defined class of consumer products under 42 U.S.C. §§ 6291(2) and 6292 — the Ninth Circuit’s examples were “refrigerators, dishwashers, and kitchen ovens”. The reason a gas-piping ban engages EPCA at all is that the court read “energy use” — “the quantity of energy directly consumed by a consumer product at point of use”, § 6291(4) — to reach a code that prevents such a product being supplied with gas.
- Electric-ready
- The 2022 Energy Code’s mandatory requirement, at sections 150.0(n) and 150.0(t)–(v), that a newly constructed building installing gas or propane space heating, water heating, cooking or clothes drying also install the dedicated circuits and reserve the labeled panel space for later electric replacement. The Commission’s stated intent: “to facilitate future installations of high efficiency electric equipment and minimize future retrofit costs.”
- Newly constructed building, versus addition
- The Energy Code classification that governs whether the electric-ready mandate applies to an ADU. Detached and newly built, or joined only by a breezeway or covered walkway, is a newly constructed building. Everything else on the Commission’s published list is an addition, and additions are outside the mandate.
What we could not verify
The roster of jurisdictions with a reach code in force. This is the page contract’s named primary dataset and we did not get it.
The California Energy Commission’s local-energy-ordinance pages returned HTTP 404 at two attempted paths, and the adopted-ordinance listing maintained by the utility-administered Statewide Reach Codes Program was unreachable — its front page loaded, its ordinance listing did not.
This edition therefore names no jurisdiction as having, or not having, an all-electric requirement. When the filings are reachable we will publish a table with a per-jurisdiction retrieval date, and not before.
What happened to individual ordinances after January 2024. Repeals, suspensions, amendments and enforcement-policy changes following the amended Berkeley opinion are exactly the kind of fact that a research page must retrieve rather than infer. We retrieved none of them and we assert none of them.
Anything about the 2025 Energy Code’s treatment of gas end uses. The Commission states the 2025 update “expand[s] the use of heat pumps in newly constructed residential buildings, encourage[s] electric-readiness,” and applies to permit applications on or after 1 January 2026.
We could not retrieve the 2025 compliance manual, so every code requirement quoted on this page is from the 2022 edition.
Whether Berkeley’s own ordinance, or any other, remains on the books. We read the opinion. We did not read any municipal code for this page, and the group A retrieval for this site records that library.municode.com returns HTTP 403 to automated retrieval, which is a standing obstacle for this desk on every ordinance question.
Questions
Can a California city ban gas in a new ADU?
What is a reach code?
Which California cities require all-electric ADUs?
Does the state require an ADU to be all-electric?
Do reach codes apply to a garage conversion ADU?
Is an all-electric ADU more expensive to build?
What is EPCA and why does it matter to a building code?
Should I plan an all-electric ADU anyway?
Written and audited by
HyreADU Research Desk
Primary-source research, data analysis and fact checking
We are a research desk, not a builder. We read the permit extract, the statute, the HCD return or the fee schedule ourselves, and publish each figure with its source and retrieval date.
Where a number cannot be traced to a primary source, we leave it out and say what we could not verify. Our store-based claims cover California only.
- CA
- the only state this desk will make store-based claims about
- 5
- jurisdictions with extracted ADU permit evidence
- 735
- CSLB-verified companies in the California store
- 0
- national claims from a one-state store
How this desk works
- Primary sources only. Permit counts come from the city or county that issued the permit. Production counts come from HCD’s Annual Progress Report. Rents come from HUD or the Census. We do not cite an article that cites a source; we download the source and compute the figure ourselves.
- This is a California site. The company store is 734 California firms and one New Mexico firm. Permit evidence exists for five named jurisdictions: Los Angeles, San Francisco, Sacramento, San José and unincorporated Marin. A number from that store is titled to those places, never to the United States.
- A permit is not a completion, and a license is not an ADU grade. California licenses no ADU classification. Being named on an ADU permit is evidence of engagement in that jurisdiction, not of quality, completion, or work anywhere else. Owner-builder permits are excluded from contractor counts.
- Calculation is labeled as calculation. Figures we derive are never presented as something HCD, HUD, the Census or a city published. Terner Center research is cited as Terner’s, never restated as ours.
- We do not design, permit or build ADUs, and we take no payment for placement, ranking or a favorable mention. Pages that look like rankings are not: they publish public-record counts and let the reader decide.
- Nothing here is legal, tax or financial advice. Zoning, underwriting and appraisal practice vary by jurisdiction, lender and appraiser. The useful next step on a specific lot is the planning counter and a licensed professional.
Data as of Public Resources Code § 25402.1 retrieved from leginfo.legislature.ca.gov 2026-09-05; California Restaurant Association v. City of Berkeley, No. 21-16278, amended opinion of 2 January 2024, retrieved as PDF from the United States Court of Appeals for the Ninth Circuit 2026-09-05; 42 U.S.C. § 6297 retrieved from the Legal Information Institute 2026-09-05; California Energy Commission compliance manual and standards pages retrieved 2026-09-05. Authorship on this site is organizational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold.
Our editorial policy sets out how we source, date and correct what we publish.
Sources & retrieval dates
- California Restaurant Association v. City of Berkeley, No. 21-16278 (9th Cir.), order and amended opinion , Retrieved as PDF from the Ninth Circuit’s document store and text-extracted 2026-09-05. D.C. No. 4:19-cv-07668-YGR. Argued and submitted 12 May 2022; filed 17 April 2023; amended 2 January 2024. Panel: O’Scannlain and Bumatay, Circuit Judges, and M. Miller Baker, Judge of the Court of International Trade, sitting by designation; opinion by Judge Bumatay. Holding as quoted: “Based on its text, structure, and context, we conclude EPCA preempts building codes like Berkeley’s Ordinance that ban natural gas piping within new buildings. Our holding here is limited.” Order denying rehearing en banc, with a dissent from denial by Judge Friedland and a statement respecting denial by Judge Berzon. Retrieved 2026-09-05.
- 42 U.S.C. § 6297 — EPCA preemption of State energy conservation standards , Subsection (c), the general rule of preemption, and subsection (f)(3), setting seven conditions a State or local building code addressing energy efficiency must satisfy — including that “[t]he code does not require that the covered product have an energy efficiency exceeding the applicable energy conservation standard,” and that energy use calculations follow the federal test procedures under section 6293. Retrieved from the Legal Information Institute. Retrieved 2026-09-05.
- California Public Resources Code § 25402.1 — local energy standards more stringent than the state code , Subdivision (h)(2) as retrieved: enforcement of local standards is permitted “if the city or county files the basis of its determination that the standards are cost effective with the commission and the commission finds that the standards will require the diminution of energy consumption levels permitted by the rules and regulations adopted pursuant to those sections.” Amended by Stats. 2024, Ch. 353, Sec. 16 (AB 1533), effective 1 January 2025. Retrieved 2026-09-05.
- California Energy Commission, 2022 Single-Family Residential Compliance Manual (CEC-400-2022-006), May 2022 , Retrieved as PDF and text-extracted 2026-09-05. Chapter 10 for the electric-ready mandatory measures quoted in the state-baseline table, including “[t]here are no electric ready requirements for additions or alterations” and “[t]here are no performance or prescriptive electric ready requirements for single family buildings.” Section 9.3.5 and Figure 9-2 for the ADU addition/newly-constructed classification. Retrieved 2026-09-05.
- California Energy Commission, 2022 Building Energy Efficiency Standards Summary (fact sheet) , Retrieved as PDF and text-extracted 2026-09-05. “The update also requires all new homes be electric-ready.” And on the practice this page is about: “after each update, many cities and counties choose to adopt standards that exceed the state minimum … Reach standards are an important tool for jurisdictions to meet their own climate goals … Historically, such local ordinances have served as a bellwether for statewide standards.” Retrieved 2026-09-05.
- California Energy Commission — 2025 Building Energy Efficiency Standards , “Buildings whose permit applications are applied for on or after January 1, 2026, must comply with the 2025 Energy Code.” The update is described as expanding “the use of heat pumps in newly constructed residential buildings, encourag[ing] electric-readiness, strengthen[ing] ventilation standards, and more.” Retrieved 2026-09-05.
- California Building Standards Commission — code editions and effective dates , The 2025 Title 24 “will be published July 1, 2025, with an effective date of January 1, 2026”; the 2022 edition “was published July 1, 2022, with an effective date of January 1, 2023.” Part 6 is the California Energy Code, the part a reach code reaches beyond. Retrieved 2026-09-05.
- Statewide Reach Codes Program (utility-administered, CPUC and CEC supported) — program site , Retrieved 2026-09-05. The program describes itself as “[c]ollaborating with cities, counties and stakeholders to drive reach code development and adoption” and is “administered by Pacific Gas and Electric Company, San Diego Gas & Electric Company (SDG&E), and Southern California Edison Company under the auspices of the California Public Utilities Commission and in support of the California Energy Commission.” Its adopted-ordinance listing was not reachable on this date, which is why this page publishes no jurisdiction table. Recorded here so the gap is auditable. Retrieved 2026-09-05.
Ask three questions in writing, and date the answers
Does this jurisdiction have an ordinance filed under Public Resources Code § 25402.1(h)(2)? Does it reach accessory dwelling units, and does it reach additions? Is the department enforcing it today? Every published list you will find is older than the answer to the third question.
HyreADU does not design, permit or build accessory dwelling units and does not practice law. This page is informational and is not legal advice.
It quotes a published appellate opinion and describes statutory and code text as retrieved on 5 September 2026; it reaches no conclusion about whether any particular ordinance is preempted, and it names no jurisdiction as having or not having an all-electric requirement.
It deliberately publishes no city list, because the underlying filings were unreachable on this date and a list compiled before January 2024 predates the ruling described here.
Gas piping and electrical work in California is licensed work under permit — a C-36 plumbing contractor for gas, a C-10 electrical contractor for electrical — and nothing on this page is instruction to perform it. Verify with your planning department, in writing, and date the answer.