SB 504: Shoring Up the Legal Foundation for Zone Zero

The gap AB 3074 left behind

When AB 3074 became law on January 1, 2021, it accomplished something important: it created Zone Zero in California statute. For the first time, the state's legal code explicitly required an ember-resistant zone within five feet of every structure in a Fire Hazard Severity Zone. The Board of Forestry and Fire Protection was directed to write the regulations, and the State Fire Marshal was tasked with developing the guidance document that would translate those regulations into practical homeowner instructions.

But AB 3074 had left several significant gaps. The original bill provided that once regulations were finalized, new construction would have to comply immediately, and existing structures would have one year to comply. This one-year window for existing homeowners was considered sufficient when the bill passed in 2020, but as the rulemaking process dragged on through 2021, 2022, and 2023 without producing final regulations, the inadequacy of that framework became clear. A homeowner discovering in 2024 that regulations had finally been adopted would have had only twelve months to achieve full compliance, a timeline that many property owners, particularly lower-income homeowners and those with complex landscaping, would struggle to meet.

There was also a question of resources. The Board of Forestry was being asked to write regulations that would affect millions of property owners across the state. Local fire agencies would be responsible for enforcement. But the grant programs and funding mechanisms to help communities prepare for and implement those requirements had not kept pace with the regulatory workload. Local agencies performing defensible space assessments and outreach were doing so with limited state support.

The rulemaking stalls

From 2021 through 2023, the Board of Forestry worked through the preliminary stages of Zone Zero rulemaking. Public workshops were held. Technical committees considered the science. Draft language was developed and revised. But the formal rulemaking process, which involves notice and comment procedures under California's Administrative Procedure Act, had not yet commenced.

The reasons were multiple. The rulemaking was contingent on a legislative appropriation, which introduced delays each budget cycle. The complexity of the regulatory question, specifying what materials were and weren't permitted in a five-foot zone that varied enormously across California's landscapes, required extensive technical and scientific deliberation. And the political environment had grown more complex, particularly as Southern California homeowners and landscaping advocates began organizing against the prospect of mandatory vegetation removal from the immediate perimeter of their homes.

By 2024, it was clear that the existing statutory framework needed reinforcement. The legislature needed to both extend the compliance window for existing homeowners and strengthen the Board's regulatory tools, particularly its authority to integrate the Zone Zero requirements into the broader defensible space framework and to require the regulations to explicitly address costs.

Senator Dodd's bill

Senate Bill 504 was authored by Senator Bill Dodd, representing California's 3rd Senate District in the North Bay, a region that had suffered through some of the state's worst wildfire disasters, including the 2017 Wine Country fires that burned through Napa and Sonoma counties and the Tubbs Fire that destroyed neighborhoods in Santa Rosa.

Dodd had a deep familiarity with the human cost of wildfire and with the frustrations of communities that had been promised stronger protections only to watch the regulatory process stall. SB 504, introduced in 2023 and signed into law on September 29, 2024 as Chapter 982 of the Statutes of 2024, was structured as a comprehensive amendment to the Zone Zero framework, not a repeal or replacement of AB 3074, but a set of targeted fixes designed to make that foundational law actually work.

The bill moved through both chambers of the legislature on consent, a strong signal of the broad, bipartisan consensus that continued to exist around Zone Zero's goals. The final vote in the Assembly was 77-0. In the Senate, concurrence in Assembly amendments passed 40-0. Governor Newsom signed it on September 29, 2024, exactly four years to the day after AB 3074 had been signed.

What SB 504 changed

SB 504 amended Sections 51182 and 51186 of the Government Code and Sections 4124.5 and 4291 of the Public Resources Code. Its core changes:

Extended the existing-structure timeline. Under AB 3074, existing structures had one year from the new-construction effective date to comply. SB 504 changed this to three years, a significant expansion of the grace period that responded directly to concerns from homeowners, local governments, and advocacy groups about the feasibility of rapid compliance.

Authorized Zone Zero integration into Zone 1. SB 504 explicitly authorized the Board's regulations to alter the fuel reduction requirements for the 5-to-30-foot zone (Zone 1) to integrate Zone Zero, recognizing that the two zones needed to be treated as a unified defensible space system rather than independent requirements. This gave the Board clearer legal authority to take a holistic approach to the 0-to-30-foot area around structures.

Required the regulations to address costs. SB 504 added a requirement that the Board's regulations explicitly consider and address the costs of compliance for property owners. This was a direct response to concerns from homeowners, particularly in high-density Southern California neighborhoods, about the financial burden of mandatory vegetation removal and replacement.

Extended Zone Zero requirements to Local Responsibility Areas. SB 504 made conforming changes to ensure that the Zone Zero requirements applied not only to properties in the State Responsibility Area but also to occupied dwellings in Very High Fire Hazard Severity Zones designated by local agencies, closing a gap in the original AB 3074 coverage.

Maintained the enforcement trigger. Like AB 3074, SB 504 preserved the requirement that enforcement changes could only begin after the State Fire Marshal made a written finding that the legislature had appropriated sufficient resources, protecting against unfunded mandates and ensuring the state's enforcement capacity kept pace with the regulatory requirements.

The grant program reforms

Beyond the regulatory changes, SB 504 made significant amendments to the state's local assistance grant program for fire prevention and home hardening education. These changes were designed to strengthen the pipeline of resources flowing to the communities that would bear the greatest burden of Zone Zero implementation.

Existing law required the Department of Forestry and Fire Protection to establish a local assistance grant program for fire prevention and home hardening education activities. SB 504 reformed this program in several ways. It required the department, when reviewing grant applications, to give priority to local governmental entities that were qualified to perform defensible space assessments in Very High and High Fire Hazard Severity Zones and that reported assessment data using the state's common reporting platform, creating an incentive for local agencies to participate in the state's data-sharing infrastructure.

The bill also required the Board's regulations to be developed with input on the costs of compliance, including consideration of assistance programs, grant funding, and other mechanisms to support lower-income homeowners in achieving Zone Zero requirements. This recognition that compliance costs would fall unevenly across property owners was a significant policy shift, moving Zone Zero from a pure regulatory mandate toward a framework that at least acknowledged the equity dimensions of large-scale property requirements.

Passage and reception

SB 504 generated relatively little controversy during its legislative journey, a testament both to the broad consensus that Zone Zero was the right policy and to the bill's targeted, technical character. Unlike AB 3074, which had a political significance as the founding statute, SB 504 was largely an implementation bill: fixing specific problems in an existing framework rather than staking out new political ground.

Fire safety advocates welcomed the three-year compliance window as a realistic accommodation for the complexity of implementation without being so long as to meaningfully delay protection. The California Fire Chiefs Association, CAL FIRE, and allied organizations continued to support the Zone Zero framework. The insurance industry, which had been a consistent advocate for stronger fire mitigation requirements as it grappled with the California home insurance crisis, supported the bill's direction.

Local government associations appreciated the grant program reforms and the cost-of-compliance provisions, which signaled that Sacramento was at least aware of the implementation burden being placed on cities and counties. The bill's passage with zero votes against in either chamber reflected a rare moment of complete legislative consensus on a complex environmental and public safety issue.

Opposition and concerns

While SB 504 itself passed without opposition, the broader Zone Zero rulemaking process it was designed to support faced significant pushback throughout 2024 and 2025. The Board of Forestry's public workshops drew thousands of comments and hours of testimony, much of it from Southern California homeowners and landscaping advocates deeply skeptical of the proposed regulations.

The core objection was not to Zone Zero as a concept but to the specific regulatory proposals, particularly the prospect of prohibiting all combustible materials, including live vegetation, within five feet of structures. Residents of Pacific Palisades, Pasadena, and other LA-area communities argued that their neighborhoods were fundamentally different from rural fire country, and that a blanket prohibition on vegetation within five feet of a home would strip away trees and gardens that had coexisted with structures for decades. Some residents testified that well-hydrated, well-maintained plants had protected their homes during the January 2025 fires.

State Senator Ben Allen, representing West Los Angeles, articulated these concerns from within the legislature: “The challenge for us in government is how do we come up with a policy that is as least restrictive as possible to respect people’s property rights and aesthetic needs while also taking the steps necessary to dramatically reduce fire risk?” The tension Allen described, between the clarity of the fire science and the complexity of real communities, would shape the Zone Zero rulemaking through 2025 and into 2026.

The Oakland Firesafe Council documented what it called a clear pattern in the fall 2025 advisory committee meetings: strong, consistent support for strict Zone Zero standards from firefighters, wildfire scientists, FireSafe and Firewise leaders, and the California Insurance Commissioner, alongside increasingly vocal objections from Southern California homeowners and landscaping interests that focused not on fire science but on preserving vegetation and aesthetics close to structures.

What happened after

SB 504 was signed in September 2024. The Zone Zero Advisory Committee, established specifically to drive the rulemaking to completion, held nearly a dozen public workshops through 2025, gathering input from homeowners, fire professionals, scientists, local governments, and advocates across California. By fall 2025, draft regulation language was near final.

The deadline established by AB 3074 and reinforced by Governor Newsom's Executive Order N-18-25, December 31, 2025, came and went without final regulations being adopted. The Zone Zero Advisory Committee resumed work in March 2026. The Board of Forestry released an updated draft in April 2026 that reflected the accumulated input from years of public engagement: a phased approach prioritizing education and outreach, flexible standards for live vegetation, and local discretion over certain implementation details.

SB 504's most durable contribution may be the three-year compliance window for existing structures. Whatever the final regulations say, homeowners will have time to understand and implement them. That breathing room, combined with the grant programs and education initiatives the bill reformed, represents the legislature's clearest acknowledgment that Zone Zero implementation must be a supported process, not just a regulatory mandate.

References & sources

• SB 504 Full Bill Text, California Legislative Information
• SB 504 Status and History, LegiScan
• SB 504 Vote History, FastDemocracy
• SB 504, CalMatters Digital Democracy
• Defensible Space Zones 0, 1 & 2, Board of Forestry
• Zone 0: When the Deadline Passed, Oakland Firesafe Council
• Zone Zero Sparks Debate Among LA Residents, ABC7
• After Devastating LA Fires, California Drafts Nation's Toughest Rules, NPR
• Zone 0 Frequently Asked Questions, Board of Forestry / CAL FIRE
• Board of Forestry April 2026 Draft, Coastside Buzz