Analysis

We read fifty-one county codes in search of Zone 0. Here is what California's local wildfire law actually says.

Fact-checked August 19, 2026·Sources at the end of this article

Why we did this

Every week someone is told that "the county" already requires a noncombustible fence, or that Zone 0 is "already the law" where they live. There is no state list of local ember-resistant-zone rules, so the only way to answer those claims is to read each jurisdiction's adopted text. We had been doing that county by county for the places we cover in depth. On August 23, 2026 we finished the job at county level: every California county whose code could be reached by any tool we have, read from the codified text its own publisher serves, with the ordinance numbers and adoption dates recorded.

The result is a negative in shape but not in value. Knowing that a county's law says nothing about the first five feet is exactly what a homeowner being quoted for a "required" fence replacement needs, and it is what nobody else publishes, because "we checked and there is nothing" earns no headlines. The full jurisdiction-level detail lives on the register, in its "checked, and there is nothing to report" section. This page is the pattern.

Finding one: county wildfire law was written in the thirty-and-one-hundred-foot era

The dominant shape, across dozens of counties, is a defensible space or fire-safe ordinance built on Public Resources Code section 4291 and the state's fire safe regulations: clear flammable vegetation within thirty feet of a structure, reduce fuel out to one hundred feet, keep roads wide and hydrants marked. The adoption dates tell the story. Sierra County's ban on smoking in flammable vegetation began as Ordinance 124 in 1928 and is still on the books. Humboldt's fire prevention chapter is Ordinance 231 of 1946, written about burn permits and waste fires. Siskiyou's fire hazard regulations date to 1968. Calaveras's hazardous fire area chapter is from 1977. Trinity and Tehama adopted the same fire-safe model in 1991. Mono and Modoc adopted theirs in 2008. Shasta rewrote its chapter in 2019 and amended it in 2025, and it is still a thirty-and-one-hundred-foot regime.

Nothing in that framework regulates what the first five feet is made of. When the statewide Zone 0 regulation takes effect, it will not be tightening county rules. It will be introducing a concept most county codes have never contained, into communities whose local law has told them for thirty years that compliance means cutting grass, not choosing materials.

Finding two: five codes will change meaning on effective day, silently

Three jurisdictions incorporated the state's defensible space regulation, Title 14 Section 1299.03 and its neighbors, into their own codes by reference:

• Calaveras County, by a February 2017 ordinance, adopted Public Resources Code sections 4291 through 4299 and Title 14 sections 1299.01 through 1299.05 wholesale into its municipal code, county-wide.
• Contra Costa County and its fire districts, by a 2023 ordinance, require defensible space "in accordance with" section 1299.03, with a documentation requirement at close of escrow attached.
• Morro Bay, by an ordinance adopted September 23, 2025, made section 1299.03 and the Board of Forestry's guidelines "the controlling standards" for its weed abatement chapter, citywide, across every hazard designation.

Two more counties point at the statutes instead of the regulation, and their codes carry the identical sentence: property "shall be maintained in accordance with the defensible space requirements contained in Government Code Section 51182... and Public Resources Code Section 4291, as applicable." Mono County wrote it in 2008, and its code stands current through a 2025 ordinance. Inyo County copied the model in 2020, in the same ordinance that designates every unincorporated acre of the county a Wildland-Urban Interface Fire Area and makes violations a public nuisance per se. The ember-resistant zone was later written into both of those statutes, to activate when the state's regulation takes effect.

Today none of these five codes requires an ember-resistant zone, because the sections and statutes they point at do not require one yet. But the state's Zone 0 package will write its requirements into exactly the places these codes point. On the day the state text takes effect, the local law of all five may begin requiring Zone 0 through their own municipal codes, in Morro Bay's case reaching parcels the state rule's own Local Responsibility Area trigger would never touch, and in Mono's and Inyo's mirroring the state duty with county enforcement behind it. Whether each incorporation is dynamic or frozen at the text as it stood is a legal question the ordinances do not answer, and we do not answer it either. We track all five on our effective-date checklist, and we may be the only ones tracking them at all.

A sixth may exist. Alpine County's fuels reduction chapter, as it stood in a 2008 archive capture, requires defensible space "in compliance with Public Resources Code Section 4291 as currently exists and as may be amended in the future." A seventeen-year-old capture cannot prove what the code says today, so Alpine sits on the watch list as a verify-first item rather than in the count of five, and the register explains exactly why.

Finding three: cities are widening where fuel rules reach, not what they require

In the 2025 code-adoption cycle, three cities amended the same section of the California Wildland-Urban Interface Code, section 604.2, which says where hazardous vegetation and fuel management applies. Santa Monica did it in October 2025. Monte Sereno and San Jose did it in November 2025, extending the duty to Moderate hazard zones and city-designated interface areas, well past the state rule's own coverage. None of the three added anything about the first five feet or fence materials.

The consequence arrives later. The statewide Zone 0 text, once effective, will apply on top of local designations that these cities have quietly broadened. A San Jose or Monte Sereno homeowner in a Moderate zone, reading only the state regulation, would conclude the rule does not reach them. Their own city code may say otherwise. This is the kind of interaction nobody's coverage explains, which is why we track it.

Finding four: the five-foot idea appears exactly once outside the register, as a bargaining chip

Lassen County's fire hazards chapter, built on the modern fire-safe model, allows a new structure that cannot meet the required thirty-foot setback to substitute alternatives providing the same practical effect, including "noncombustible block walls or fences" and "five feet of noncombustible material horizontally around the structure." That is the ember-resistant zone concept, present in a county code as an optional trade for a setback nobody could meet, years before the state made any of it mandatory. In fifty-one county codes, that is the closest thing to Zone 0 we found outside the eighteen jurisdictions that actually adopted one.

What we could not read, named plainly

Seven counties sit behind code publishers that refuse every tool we have: Alpine, Amador, Del Norte, Glenn, Mariposa, Sacramento and Solano. Five of them we could partially read, and the register carries what each partial read found: Mariposa's publisher shows zero results for "defensible" and an unread 2025 wildland code adoption; Del Norte's shows the 1991 fire-safe model; Solano's archived building chapter adopts the 2021 International Wildland-Urban Interface Code without amendment while its "Abatement of Fire Hazards" chapter has no archived copy at all; and Amador and Alpine were read in depth from archives too old to trust, 2013 and 2008, including one Alpine sentence interesting enough to put on our effective-date watch list. Glenn and Sacramento are fully dark: their current publishers exist but block every tool, hold no usable archive, and Sacramento's most common code link turns out to point at the city rather than the county. We do not count a county as surveyed until its fire text is read from a reasonably current capture, so all seven stay off the surveyed list. If you live in one of them and can obtain the county's fire or vegetation ordinance, the register page says how to send it to us, and we will read it.

Three counties came off this list the day we published it. Humboldt's, Sierra's and Colusa's publishers all block direct access, but a public web archive turned out to hold their pages in depth, dated by the publishers' own banners: Humboldt through an October 2025 ordinance, Sierra through a December 2023 one, Colusa's fire chapter as served in March 2024. We read the operative fire chapters from the archived pages, found nothing about the first five feet in any of the three, and found the two oldest fire laws in the survey, from 1946 and 1928, plus Colusa's signature rule: a three-foot firebreak around grain fields, written for rice country. The handful of sections with no archived copy are named on the register rather than guessed at. All three count as surveyed as of their archived codification dates, and their entries say exactly that.

The same honesty applies below county level. California has hundreds of cities and fire protection districts with independent ordinance authority, and no survey of counties covers them. Where we read city and district codes, the register's county entries say so, and where we could not, they say that instead.

What this means for you

• If someone says your county already requires a noncombustible fence, ask for the section number. In fifty-one counties we found no such requirement outside the register's eighteen jurisdictions. The claim is checkable in minutes, and we have usually already checked it.
• If you live in Calaveras, Contra Costa Fire's territory, Morro Bay, Mono County or Inyo County, your local code is wired to the state's defensible space law. When the state's Zone 0 text takes effect, ask your fire authority how your jurisdiction reads its own incorporation. Our status tracker will flag the day that question becomes live.
• If you live in San Jose, Monte Sereno or Santa Monica, your city has broadened where fuel-management duties apply. The state rule's arrival will mean more there than its own text suggests.
• Everywhere else, the thirty-and-one-hundred-foot duties are the law today. Cut the grass, clear the roof, keep the hundred feet. The five-foot materials rules arrive with the state regulation, on the timeline our timeline page tracks, and nothing about that timeline requires buying anything today.

Method, so you can check us

Every county was read from the codified text served by its own code publisher, through the publisher's public pages or data services, current through the codification date each publisher states. Where a county self-publishes its code as documents, we read the county's posted files. Where an ordinance existed only as an image scan, we read it page by page from the images and say so. Where a publisher blocks direct access but a public web archive holds its pages, we read the archived pages, record the codification date they state, and mark the finding as dated rather than current. Findings are recorded with ordinance numbers and adoption dates in our fact base, and the register's negative entries carry the same citations. If you find a county provision we missed, we publish corrections on the page where the error appeared, dated.