CWUIC · California Wildland-Urban Interface Code
How are Fire Hazard Severity Zones defined and organized?
The State Fire Marshal maps and rates Fire Hazard Severity Zones using factors like fuel loading, slope, fire weather and winds; those maps are periodically reviewed (every 5 years), reproduced in State files, and local agencies can adopt ordinances that increase (but not decrease) zone severity. file
Last reviewed: July 6, 2026
What the code requires — plain English
The State Fire Marshal is responsible for mapping and classifying lands into Fire Hazard Severity Zones and assigning each zone a severity rating based on the expected fire hazard. The classification must group relatively homogeneous lands and be based on fuel loading, slope, fire weather and other relevant factors (including wind patterns) — see § 302.1.
The single most important rule: the State Fire Marshal designates Fire Hazard Severity Zones and assigns ratings using consistent statewide criteria (fuel, slope, weather and winds). § 302.1.
Requirements in detail
Who designates the zones
- Designating authority: The State Fire Marshal (maps and assigns zone ratings) — § 302.1.
- Local authority: A local agency may adopt ordinances to designate Moderate, High, or Very High zones within its jurisdiction consistent with the State’s recommendations and, in limited circumstances, may expand the areas designated by the State (but may not reduce a State-identified zone level) — see Government Code provisions referenced in the CWUIC (e.g., § 51178 and § 51179).
What factors must be considered
The classification must embrace relatively homogeneous lands and be based on:
- Fuel loading
- Slope
- Fire weather
- Other relevant factors, including areas where winds are a major cause of wildfire spread These factor requirements are specified in § 302.1. Note: the CWUIC (in § 302.1 and cross-referenced statutes) lists the factors but does not publish numeric cutoffs for slope or fuel loading inside § 302.1 itself — mapping uses statewide criteria adopted by the State Fire Marshal/Boards.
How maps and ratings are adopted and published
- The State Fire Marshal adopts regulatory designations and ratings and must follow notice and hearing requirements in the cited statutes (e.g., advance county notice periods) when adopting zone designations and ratings. See the cross-references in the CWUIC to Public Resources Code sections used by the State Fire Marshal.
- The official SRA Fire Hazard Severity Zone map is filed and available through the Office of the State Fire Marshal (see Title 19 references incorporated into the CWUIC).
Review and update cycle
- Review frequency: Wildland-urban interface area designations (and State-identified zones) must be periodically reviewed; the code specifically directs a re-evaluation on a 5-year basis (or more frequently if needed) — § 302.2.
Decision-relevant dimensions (quick reference table)
| Dimension | Relevant values / actions | Code Reference |
|---|---|---|
| Designating authority | State Fire Marshal (primary); local agencies may adopt ordinances that increase designation levels in their jurisdiction | § 302.1, Government Code §51179 |
| Classification basis | Fuel loading, slope, fire weather, winds, and other relevant factors | § 302.1 |
| Zone ratings | Moderate, High, Very High (State assigns ratings using statewide criteria) | Gov. Code §51178 (reprinted in CWUIC appendices) |
| Map publication | Official maps maintained by State Fire Marshal; Title 19 references file the map (OSFM website) | Title 19 / §2201 referenced in CWUIC Appendix H |
| Public/agency timing | State: advance county notice/hearing process; Local agency: must adopt ordinance within 120 days after receiving State recommendations (where applicable) | PRC §4203 / Gov. Code §51179 (cited in CWUIC) |
| Review cadence | Every 5 years or sooner as needed | § 302.2 |
Exceptions & special cases
- Local agencies may increase the level of fire hazard severity within their jurisdiction (for example, designate additional areas as Very High) after findings supported by substantial evidence — they may not decrease a level assigned by the State. See the CWUIC discussion of Government Code procedures (e.g., § 51179).
- The CWUIC incorporates and cross-references Public Resources Code and Government Code sections (PRC §§4201–4204 and GC §§51175–51189). Some implementation details (for example, the State’s formal rating criteria and notice/hearing steps) are handled in those statutes and the State Fire Marshal’s regulations rather than as prescriptive numeric thresholds in § 302.1 itself.
- The official SRA map is maintained by the Office of the State Fire Marshal and incorporated by Title 19 reference; local amendments or local adoption require public posting/transmittal as described in the referenced statutes (see CWUIC appendices).
If you need the State’s specific numeric criteria (e.g., fuel-model thresholds, slope bands, or GIS-based indices) the CWUIC directs users to the State Fire Marshal’s regulations and the cited PRC/Gov Code sections; those numeric criteria are not printed verbatim in § 302.1 of the CWUIC text returned here.
Common mistakes
- Treating the published map as purely advisory: the State Fire Marshal’s mapped zones carry regulatory effect for SRA lands and trigger CWUIC provisions; local jurisdictions must act (or may adopt stricter designations) — see § 302.1 and the Government Code cross-references.
- Assuming numeric cutoffs are in § 302.1: the code lists factors (fuel loading, slope, fire weather, winds), but does not provide the detailed numeric thresholds inside § 302.1 — those are established by the State Fire Marshal’s regulations and referenced statutes.
- Missing required timelines and notice steps: the State’s adoption process and local adoption/transmittal timelines (e.g., county notices, local agency 120‑day designation window) are specified in the statutes the CWUIC references — failing to follow those procedures is a common procedural error.
- Forgetting map posting and public availability requirements: after State transmittal, local agencies must make maps available for public review and follow posting/transmittal rules (see the CWUIC appendices and Gov. Code references).
Worked example — applying the rule (timeline + decisions)
Scenario: County A receives recommended zone map material from the State Fire Marshal on January 10.
Step 1 — State transmittal and public notice
- The State Fire Marshal transmitted the recommended designations and ratings (process governed by PRC/Gov Code cross‑references incorporated into CWUIC). In the State adoption process the County would have had advance notice and opportunity for hearing as required by statute (advance county notice/hearing provisions are part of the State regulatory process referenced in the CWUIC).
Step 2 — Local agency action window
- Under the Government Code steps cited in the CWUIC, after receiving the State Fire Marshal’s transmittal the local agency must act to adopt Moderate/High/Very High zones within 120 days if adopting an ordinance based on the State’s recommendation (the CWUIC reproduces and refers to these Government Code procedures) — so County A would have until May 10 to adopt a conforming ordinance or submit changes supported by evidence. § 302.1 and Gov. Code §51179 (as printed in CWUIC appendices).
Step 3 — Technical classification of a parcel (how the factors are applied)
- Suppose Parcel X is on a 30‑acre slope with dense chaparral, average slope exposure toward prevailing dry winds, and historical fire weather showing frequent critical conditions. Using the CWUIC criteria (fuel loading, slope, fire weather, winds) the mapping team would evaluate Parcel X’s combination of factors and, given high fuel loading + steep slope + critical weather + wind exposure, the State is likely to classify it as a Very High Fire Hazard Severity Zone. The CWUIC requires those factors be used for classification but does not provide a single numeric slope/fuel threshold inside § 302.1; the actual rating decision uses the State’s adopted technical criteria and mapping methodology referenced in the CWUIC appendices.
Step 4 — After designation: posting and review
- Once County A adopts its ordinance or map amendment, the local agency must make the information available for public review and post notices as required by the statutes the CWUIC references (e.g., public availability and posting requirements in the Government Code/PRC excerpts included in the CWUIC appendices). If County A decides to increase the severity for any area, it must record findings supported by substantial evidence.
Notes about numbers in this example
- The CWUIC provides explicit timeline numbers for agency actions (e.g., 120 days for local adoption, 5 years for periodic review, 45-day advance notice in some State adoption steps) but does not supply numeric slope or fuel‑loading cutoffs inside § 302.1 itself; those technical thresholds come from the State Fire Marshal’s adopted criteria and related regulations referenced in the CWUIC.
Related provisions (in the CWUIC / appendices)
- § 302.2 — Review of wildland‑urban interface areas; 5‑year reevaluation cycle.
- § 301.2 — Purpose and intent of wildland‑urban interface area classification.
- Government Code excerpts (as printed in CWUIC Appendices) — § 51178, § 51179, § 51182 — State criteria for Moderate/High/Very High zones; local agency designation rules; and defensible‑space requirements referenced when zones are adopted.
- Title 19 / PRC cross‑references in Appendix H (e.g., Title 19 §2201; PRC §§4201–4204) — map filing and State rulemaking/notice requirements.
- Chapter 6 / Sections on vegetation management and defensible space (e.g., fuel modification distances and landscape-plan requirements) that apply to properties within Fire Hazard Severity Zones.
Code references
Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:
CWUIC § 302.1 High relevance — show source text
SECTION 302—WILDLAND-URBAN INTERFACE AREA DESIGNATIONS
302.1 Mapping . The State Fire Marshal shall classify lands into Fire Hazard Severity Zones in accordance with California Public Resources Code, Sections 4201 through 4204 for State Responsibility Areas and in accordance with Government Code, Sections 51175 through 51189 for Local Responsibility Areas. The State Fire Marshal shall designate areas in the state as fire hazard severity zones and assign each zone based on the severity of fire hazard that is expected to prevail in those areas. Each fire hazard severity zone shall embrace relatively homogeneous lands, and the classification shall be based on fuel loading, slope, fire weather and other relevant factors including areas where winds have been identified by the Office of the State Fire Marshal as a major cause of wildfire spread and other areas designated by the enforcing agency to be at a significant risk from wildfires.
302.2 Review of wildland-urban interface areas. The code official shall reevaluate and recommend modification to the wildlandurban interface areas in accordance with Section 302.1 on a 5-year basis or more frequently as deemed necessary by the legislative body. The State Fire Marshal shall periodically review the areas in the state identified as fire hazard severity zones and, as necessary, shall make recommendations relative to fire hazard severity zones. This review shall coincide with the review of state responsibility area lands every five years and, when possible, fall within the time frames for the county’s general plan update.
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CALIFORNIA WILDLAND-URBAN INTERFACE CODE – MATRIX ADOPTION TABLE
CHAPTER 4 – WILDLAND-URBAN INTERFACE AREA REQUIREMENTS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CWUIC § 1.5 High relevance — show source text
The California Code of Regulations (CCR), Title 14, Division 1.5 provisions that are found in the California Wildland-Urban Interface Code are not listed in the Matrix Adoption Tables as they are not within the State Fire Marshal’s authority to adopt. These provisions are a reprint from the current CCR, Title 14, Division 1.5 text for the code user’s convenience only and are identified in the body of the code by square brackets containing references to applicable Title 14 sections.
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3 WILDLAND-URBAN INTERFACE AREAS
User notes:
About this chapter: Chapter 3 provides for the fundamental aspect of applying the code—the legal declaration and establishment of wildlandurban interface areas within the adopting jurisdiction, mapping of the area, periodic review and updates.
SECTION 301—GENERAL
301.1 Scope. The provisions of this chapter provide methodology to establish and record wildland-urban interface areas in accor- dance with California Public Resources Code (PRC) and California Government Code (GC).
301.2 Purpose . The purpose of this chapter is to classify lands in the state in accordance with the level of fire hazard present for the purpose of identifying measures that will retard the rate of spread and reduce the potential intensity of uncontrolled fires that threaten to destroy resources, life or property, and to require that those measures be taken.
SECTION 302—WILDLAND-URBAN INTERFACE AREA DESIGNATIONS
302.1 Mapping . The State Fire Marshal shall classify lands into Fire Hazard Severity Zones in accordance with California Public Resources Code, Sections 4201 through 4204 for State Responsibility Areas and in accordance with Government Code, Sections 51175 through 51189 for Local Responsibility Areas. The State Fire Marshal shall designate areas in the state as fire hazard severity zones and assign each zone based on the severity of fire hazard that is expected to prevail in those areas. Each fire hazard severity zone shall embrace relatively homogeneous lands, and the classification shall be based on fuel loading, slope, fire weather and other relevant factors including areas where winds have been identified by the Office of the State Fire Marshal as a major cause of wildfire spread and other areas designated by the enforcing agency to be at a significant risk from wildfires.
302.2 Review of wildland-urban interface areas. The code official shall reevaluate and recommend modification to the wildlandurban interface areas in accordance with Section 302.1 on a 5-year basis or more frequently as deemed necessary by the legislative body. The State Fire Marshal shall periodically review the areas in the state identified as fire hazard severity zones and, as necessary, shall make recommendations relative to fire hazard severity zones. This review shall coincide with the review of state responsibility area lands every five years and, when possible, fall within the time frames for the county’s general plan update.
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CWUIC § 302.2 High relevance — show source text
Each fire hazard severity zone shall_ embrace relatively homogeneous lands, and the classification shall be based on fuel loading, slope, fire weather and other relevant factors including areas where winds have been identified by the Office of the State Fire Marshal as a major cause of wildfire spread and other areas designated by the enforcing agency to be at a significant risk from wildfires.
302.2 Review of wildland-urban interface areas. The code official shall reevaluate and recommend modification to the wildlandurban interface areas in accordance with Section 302.1 on a 5-year basis or more frequently as deemed necessary by the legislative body. The State Fire Marshal shall periodically review the areas in the state identified as fire hazard severity zones and, as necessary, shall make recommendations relative to fire hazard severity zones. This review shall coincide with the review of state responsibility area lands every five years and, when possible, fall within the time frames for the county’s general plan update.
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CALIFORNIA WILDLAND-URBAN INTERFACE CODE – MATRIX ADOPTION TABLE
CHAPTER 4 – WILDLAND-URBAN INTERFACE AREA REQUIREMENTS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting Agency BSC BSC-
CGSFM Col5 HCD Col7 Col8 DSA Col10 OSHPD Col12 Col13 Col14 Col15 Col16 BSCC DPH AGR DWR CEC CA SL SLC Adopting Agency BSC BSC-
CGT-24 T-19* 1 2 1/AC AC SS 1 1R 2 3 4 5 5 5 5 5 5 5 5 5 Adopt Entire Chapter Adopt Entire Chapter as
amended (amended sections
listed below)X Adopt only those sections that
are listed below[California Code of Regulations,
Title 19, Division 1]Chapter / Section 402 † 402.1.1 X 402.1.2 X 402.1.2.1 X 402.2.1 X 402.2.2 X 402. CWUIC § 51178.5. High relevance — show source text
It is the intent of the Legislature that this chapter apply to all local agencies,_ including, but not limited to, charter cities, charter counties, and charter cities and counties. This subdivision shall not limit the authority of a local agency to impose more restrictive fire and public safety requirements, as otherwise authorized by law. (c) It is not the intent of the Legislature in enacting this chapter to limit or restrict the authority of a local agency to impose more restrictive fire and public safety requirements, as otherwise authorized by law. 51176. The purpose of this chapter is to classify lands in the state in accordance with whether a very high fire hazard is present so that public officials are able to identify measures that will retard the rate of spread, and reduce the potential intensity, of uncon- trolled fires that threaten to destroy resources, life, or property, and to require that those measures be taken. 51178. The State Fire Marshal shall identify areas in the state as moderate, high, and very high fire hazard severity zones based on consistent statewide criteria and based on the severity of fire hazard that is expected to prevail in those areas. Moderate, high, and very high fire hazard severity zones shall be based on fuel loading, slope, fire weather, and other relevant factors including areas where winds have been identified by the Office of the State Fire Marshal as a major cause of wildfire spread. 51178.5. Within 30 days after receiving a transmittal from the State Fire Marshal that identifies fire hazard severity zones pursuant to Section 51178, a local agency shall make the information available for public review and comment. The information shall be presented in a format that is understandable and accessible to the general public, including, but not limited to, maps.
51179.
(a) A local agency shall designate, by ordinance, moderate, high, and very high fire hazard severity zones in its jurisdiction within 120 days of receiving recommendations from the State Fire Marshal pursuant to Section 51178. (b) (1) A local agency may, at its discretion, include areas within the jurisdiction of the local agency, not identified as very high fire hazard severity zones by the State Fire Marshal, as very high fire hazard severity zones following a finding supported by substantial evidence in the record that the requirements of Section 51182 are necessary for effective fire protection within the area.
(2) A local agency may, at its discretion, include areas within the jurisdiction of the local agency, not identified as moderate and high fire hazard severity zones by the State Fire Marshal, as moderate and high fire hazard severity zones, respectively. (3) A local agency shall not decrease the level of fire hazard severity zone as identified by the State Fire Marshal for any area within the jurisdiction of the local agency, and, in exercising its discretion pursuant to paragraph (2), may only increase the level of fire hazard severity zone as identified by the State Fire Marshal for any area within the jurisdiction of the local
agency. (c) The local agency shall transmit a copy of an ordinance adopted pursuant to subdivision (a) to the State Board of Forestry and Fire Protection within 30 days of adoption. (d) Changes made by a local agency to the recommendations made by the State Fire Marshal shall be final and shall not be rebut- table by the State Fire Marshal.
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APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS
CWUIC § 1-3 High relevance — show source text
Appendix C contains a preliminary Community WUI Fire Hazard Evaluation Framework as a suggested methodology to begin to support communities at risk in the identification of their unique hazards and to provide common metrics for comparisons between communities. This preliminary framework includes information on community size, population and fuels; on notification and evacuation; and on the community infrastructure and firefighting response potential. Aspects of this framework may already be included in various community- level documents, such as Community Wildfire Protection Plans or evacuation plans. Development of a standard framework will (1) consolidate relevant WUI fire hazard and planning information in one place, and (2) allow for cross-community comparisons.
The evaluation required to implement this framework will support prefire hazard assessment and during-fire response operations. An increased understanding of fire evacuation, fire structural response and fire defensive action relationships is needed to assess the over- all community WUI fire hazard. The quantification of these relationships will enable communities to optimize the community-level response to WUI fire hazards in a more integrated approach and result in increased life safety and reduced losses.
Appendix D Model Ordinance for Fire Hazard Severity Zone Adoption.
Appendix D is an informational appendix that is a sample ordinance designed as guidance for a city, county, city and county, or fire district to establish and designate fire hazard severity zones within their jurisdiction.
Appendix E Reserved.
Appendix F Characteristics of Fire-Smart Vegetation.
Appendix F is an informational appendix provided for the convenience of the code user. It is simply a compilation of the eight characteristics of fire-smart vegetation that can be used effectively within wildland-urban interface areas to reduce the likelihood of fire spread through vegetation.
Appendix G Voluntary Home-Hardening Recommendations.
Appendix G is an informational appendix that provides discussion of some elements of the proposed self-defense mechanisms and their role in enhancing the protection of exposed structures in the wildland-urban interface. The items provided in this appendix provide owners with suggestions for increasing the survivability of their structure. These items are not mandatory but can be considered by owners to increase the safety of structures.
Appendix H Referenced California Documents.
Appendix H contains portions of California statutes and regulations located in other documents. They are reprinted in Appendix H to aid the user in understanding the requirements applicable to wildland-urban interface areas and to provide a background for the provi- sions. Much of the text in the CWUIC is based on the requirements found in these other documents.
Appendix I Board of Appeals.
Appendix I contains the provisions for appeal and the establishment of a board of appeals. The provisions include the application for an appeal, the makeup of the board of appeals and the conduct of the appeal process.
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CONTENTS
CHAPTER 1 ADMINISTRATION. . . . . . . . . . . . . . . . . . . . . . .1-3
DIVISION I CALIFORNIA ADMINISTRATION
1.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
CWUIC § 1-2 High relevance — show source text
CHAPTER TOPICS Col2 CHAPTER SUBJECT 1-2 Administration and Definitions 3-4 Wildland-Urban Interface Area Designation and Requirements 5 Building Construction Regulations 6 Fire Protection Requirements 7 Referenced Standards Appendices A-I Adoptable and Informational Appendices Chapter 1 Scope and Administration.
Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.
Chapter 2 Definitions.
Chapter 2 is the repository of the definitions of terms used in the body of the code. The user of the code should be familiar with and consult this chapter because the definitions are essential to the correct interpretation of the code and because the user may not be aware that a term is defined.
Chapter 3 Wildland-Urban Interface Areas.
Chapter 3 provides for the fundamental aspect of applying the code—the legal declaration and establishment of wildland-urban interface areas within the adopting jurisdiction, mapping of the area, periodic review and updates.
Chapter 4 Wildland-Urban Interface Area Requirements.
The requirements of Chapter 4 apply to all occupancies in the wildland-urban interface and pertain to all of the following:
Fire service access to the property that is to be protected, including fire apparatus access roads and off-road driveways.
Premises identification.
Key boxes to provide ready access to properties secured by gated roadways or other impediments to rapid fire service access.
Fire protection water supplies, including adequate water sources, pumper apparatus drafting sites, fire hydrant systems and system reliability.
Fire department access to equipment such as fire suppression equipment and fire hydrants.
Chapter 5 Special Building Construction Regulations.
The regulations in Chapter 5 establish minimum standards for the location, design and construction of buildings and structures based on construction within a Fire Hazard Severity Zone or a Wildland-Urban Interface (WUI) Area.
The construction provisions of Chapter 5 are intended to supplement the requirements of the California Building Code and Califor- nia Residential Code and address mitigation of the unique hazards posed to buildings by wildfire and to reduce the hazards of building fires spreading to wildland fuels. This is accomplished by requiring ignition-resistant construction materials.
Chapter 6 Fire Protection Requirements.
Chapter 6 contains additional requirements for development and construction in Local Responsibility Areas (LRA) designated as Very High Fire Hazard Severity Zones and areas designated by the State Fire Marshal as State Responsibility Areas (SRA). While many of these provisions are found in Title 14 and Title 19 of the California Code of Regulations, they are replicated here for the code user. The local jurisdiction has the authority to apply the same regulations to LRA when the regulations are adopted by local ordinance.
The requirements in this chapter reference the process for adoption of Very High Fire Hazard Severity Zones in the LRA; criteria for evaluating existing subdivisions that are at significant fire risk and are without an adequate secondary egress; and criteria for fire safety provisions required in the Safety Element of a city or county General Plan.
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CWUIC § 11340.6 High relevance — show source text
4203.
(a) The State Fire Marshal shall, by regulation, designate fire hazard severity zones and assign to each zone a rating reflecting the degree of severity of fire hazard that is expected to prevail in the zone. (b) No designation of a zone and assignment of a rating shall be adopted by the State Fire Marshal until the proposed regulation has been transmitted to the board of supervisors of the county in which the zone is located at least 45 days before the adoption of the proposed regulation and a public hearing has been held in that county during that 45-day period. 4204. The State Fire Marshal shall periodically review zones designated and rated pursuant to this article and, as necessary, shall revise zones or their ratings or repeal the designation of zones. Any revision of a zone or its rating or any repeal of a zone shall conform to the requirements of Section 4203. In addition, the revision or repeal of a zone may be petitioned pursuant to Sections 11340.6 and 11340.7 of the Government Code.
4290.
(a) The board shall adopt regulations implementing minimum fire safety standards related to defensible space that are applicable to state responsibility area lands under the authority of the department, and to lands classified and designated as very high fire hazard severity zones, as defined in subdivision (i) of Section 51177 of the Government Code. These regulations apply to the perimeters and access to all residential, commercial, and industrial building construction within state responsibility areas approved after January 1, 1991, and within lands classified and designated as very high fire hazard severity zones, as defined in subdivision (i) of Section 51177 of the Government Code after July 1, 2021. The board may not adopt building standards, as defined in Section 18909 of the Health and Safety Code, under the authority of this section. As an integral part of fire safety stan- dards, the State Fire Marshal has the authority to adopt regulations for roof coverings and openings into the attic areas of buildings specified in Section 13108.5 of the Health and Safety Code. The regulations apply to the placement of mobile homes as defined by National Fire Protection Association standards. These regulations do not apply where an application for a build- ing permit was filed prior to January 1, 1991, or to parcel or tentative maps or other developments approved prior to January 1, 1991, if the final map for the tentative map is approved within the time prescribed by the local ordinance. The regulations shall include all of the following: (1) Road standards for fire equipment access. (2) Standards for signs identifying streets, roads, and buildings. (3) Minimum private water supply reserves for emergency fire use. (4) Fuel breaks and greenbelts. (b) The board shall, on and after July 1, 2021, periodically update regulations for fuel breaks and greenbelts near communities to provide greater fire safety for the perimeters to all residential, commercial, and industrial building construction within state responsibility areas and lands classified and designated as very high fire hazard severity zones, as defined in subdivision (i) of Section 51177 of the Government Code, after July 1, 2021. These regulations shall include measures to preserve undeveloped
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APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS
CWUIC § 11340.6 High relevance — show source text
The_ guidance document shall include, but not be limited to, regionally appropriate vegetation management suggestions that preserve and restore native species that are fire resistant or drought tolerant, or both, minimize erosion, minimize the spread of flammable nonnative grasses and weeds, minimize water consumption, and permit trees and shrubs near homes for shade, aesthetics, and habitat; and suggestions to minimize or eliminate the risk of flammability of nonvegetative sources of combus- tion such as woodpiles, propane tanks, decks, and outdoor lawn furniture. (2) On or before January 1, 2023, the State Board of Forestry and Fire Protection, in consultation with the Office of the State Fire Marshal, shall update the guidance document to include suggestions for creating an ember-resistant zone within five feet of a structure based on regulations promulgated by the State Board of Forestry and Fire Protection, in consultation with the Office of the State Fire Marshal, to consider the elimination of materials in the ember-resistant zone that would likely be ignited by embers.
(d) For purposes of this section, a structure for the purpose of an ember-resistant zone shall include any attached deck. This section does not limit the authority of the State Board of Forestry and Fire Protection or the Office of the State Fire Marshal to require the removal of fuel or vegetation on top of or underneath a deck pursuant to this section.
SECTION H103—CALIFORNIA PUBLIC RESOURCES CODE
Sections 4201–4204; 4290–4291.
4201. The purpose of this article is to provide for the classification of lands within state responsibility areas in accordance with the severity of fire hazard present for the purpose of identifying measures to be taken to retard the rate of spreading and to reduce the potential intensity of uncontrolled fires that threaten to destroy resources, life, or property. 4202. The State Fire Marshal shall classify lands within state responsibility areas into fire hazard severity zones. Each zone shall embrace relatively homogeneous lands and shall be based on fuel loading, slope, fire weather, and other relevant factors pres- ent, including areas where winds have been identified by the department as a major cause of wildfire spread.
4203.
(a) The State Fire Marshal shall, by regulation, designate fire hazard severity zones and assign to each zone a rating reflecting the degree of severity of fire hazard that is expected to prevail in the zone. (b) No designation of a zone and assignment of a rating shall be adopted by the State Fire Marshal until the proposed regulation has been transmitted to the board of supervisors of the county in which the zone is located at least 45 days before the adoption of the proposed regulation and a public hearing has been held in that county during that 45-day period. 4204. The State Fire Marshal shall periodically review zones designated and rated pursuant to this article and, as necessary, shall revise zones or their ratings or repeal the designation of zones. Any revision of a zone or its rating or any repeal of a zone shall conform to the requirements of Section 4203. In addition, the revision or repeal of a zone may be petitioned pursuant to Sections 11340.6 and 11340.7 of the Government Code.
4290.
(a) The board shall adopt regulations implementing minimum fire safety standards related to defensible space that are applicable to state responsibility area lands under the authority of the department, and to lands classified and designated as very high _fire hazard severity zones, as defined in subdivision (i) of Section 51177 of the Government Code.
CWUIC § 1299.05 High relevance — show source text
1299.05 Alternative methods. The provisions of these regulations are not intended to exclude alternative methods not specifically prescribed by these regulations. A fire expert designated by the Director may approve alternative practices which provide for the same practical effects as those stated in these regulations.
SECTION H105—CALIFORNIA CODE OF REGULATIONS, TITLE 19
Section 2201.
2201 Fire Hazard Severity Zones in the SRA. The fire hazard severity zones and the rating reflecting the degree of severity of fire hazard that is expected to prevail in those zones, shall be designated by the State Fire Marshal and delineated on a map on file in the Sacra- mento Office of the Department of Forestry and Fire Protection, Office of the State Fire Marshal, Fire and Resources Assessment Program, 715 P Street.
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APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS
The map, approved by the Office of the State Fire Marshal, is hereby incorporated by reference and entitled “State Responsibility Area Fire Hazard Severity Zones,” dated September 29, 2023.
The official map is also filed electronically on the following website: https://osfm.fire.ca.gov/fire-hazard-severity-zones
SECTION H106—HEALTH AND SAFETY CODE
Sections 13869.7, 17958, 18941.5.
13869.7.
(a) Any fire protection district organized pursuant to Part 2.7 (commencing with Section 13800) of Division 12 may adopt building standards relating to fire and panic safety that are more stringent than those building standards adopted by the State Fire Marshal and contained in the California Building Standards Code. For these purposes, the district board shall be deemed a legislative body and the district shall be deemed a local agency. Any changes or modifications that are more stringent than the requirements published in the California Building Standards Code relating to fire and panic safety shall be subject to subdivi- sion (b) of Section 18941.5. (b) Any fire protection district that proposes to adopt an ordinance pursuant to this section shall, not less than 30 days prior to noticing a proposed ordinance for public hearing, provide a copy of that ordinance, together with the adopted findings made pursuant to subdivision (a), to the city, county, or city and county where the ordinance will apply. The city, county, or city and county, may provide the district with written comments, which shall become part of the fire protection district’s public hearing record.
(c) The fire protection district shall transmit the adopted ordinance to the city, county, or city and county where the ordinance will apply. The legislative body of the city, county, or city and county, may ratify, modify, or deny an adopted ordinance and trans- mit its determination to the district within 15 days of the determination. Any modification or denial of an adopted ordinance shall include a written statement describing the reasons for any modifications or denial. No ordinance adopted by the district _shall be effective until ratification by the city, county, or city and county where the ordinance will apply.
CWUIC § 403.2 High relevance — show source text
APPENDIX I-4 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
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Access Applicability 402 Driveways 403.2 Fire apparatus access roads 403.3 Grade 403.7
Individual structures 402.2 Marking of roads 402.3, 403.4 Restricted 403.1
Subdivisions 402.1 Accessory Buildings and Miscellaneous Structures
Defined 202
Detached 504.11 Exempt from permit 105.3 Additions or Alterations 101.5
Address Markers 402.3 Agriculture 202 Alternative Materials or Methods 104.2.2
Appeals 112 Appendices 101.2.1 Applicable Building 202 Applicability 102 Approved 202 Approved Agency 104.2.2.6.1, 202 Authority of Code Official 104
Building 202 Building Official 202
Certificate of Completion 111 Certificate of occupancy 111.2 Revocation 111.4
Temporary occupancy 111.3
Code Official 202 Code Official, Authority 104 Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Appendix C Compliance Alternatives 105 Construction Documents 106
Amended 106.10
Examination of 106.9 Information on plans and specifications 106.2 Phased 106.12
Previous approval 106.11 Retention of 106.8 Site plan 106.3 Vegetation management plans 106.4 Control of Storage Appendix A, A105 Critical Fire Weather 202
Dead-end Road 202 Defensible Space 403, 601.3 Vegetation Plan 603 Definitions 202 Designation of Wildland-Urban Interface Area 302.1
Director 202 Driveway 202 Dumping Appendix A, A106 Dwelling 202
Exterior Covering 202
INDEX
Fees 109 Findings of Fact Appendix E Fire Chief 202 Fire Danger Rating System Appendix D Fire Flow Calculation Area Application 404.5 Defined 202 Fire Hazard Severity Zones 1.1.2, 202, 302.1, 302.2, Appendix D, Appendix H Fire Protection Plans 602
Fire Weather 202
Fire-Resistance-Rated Construction 501.3 Fire-Resistive Vegetation Appendix F Fire-Retardant-Treated Lumber or
Wood 503.2, 504.5, 504.7, 504.11 Flame Spread Index 202 Flashing 504.2.1, 504.5.1 Fuel Break 202, 609 Fuel Models Appendix D Fuel Modification 202
Fuel Modification Distance 603.2
Fuel Mosaic 202 Fuel-Loading 202
General Requirements Appendix A Green Belt 202
Greenways 202
CWUIC § 2-5 High relevance — show source text
WILDFIRE. An uncontrolled fire spreading through vegetative fuels that threatens to destroy life, property or resources as defined in Public Resources Code Sections 4103 and 4104.
WILDFIRE EXPOSURE. One or a combination of radiant heat, convective heat, direct flame contact and burning embers being projected by vegetation fire to a structure and its immediate environment.
WILDLAND. An area in which development is essentially nonexistent, except for roads, railroads, power lines and similar facilities.
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 2-5
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DEFINITIONS
WILDLAND-URBAN INTERFACE AREA. A geographical area identified by the state as a “Fire Hazard Severity Zone” in accordance with the Public Resources Code Sections 4201 through 4204 and Government Code Sections 51175 through 51189, and other areas designated by the enforcing agency to be at a significant risk from wildfires.
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CALIFORNIA WILDLAND-URBAN INTERFACE CODE – MATRIX ADOPTION TABLE
CHAPTER 3 – WILDLAND-URBAN INTERFACE AREAS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting Agency BSC BSC-
CGSFM Col5 HCD Col7 Col8 DSA Col10 OSHPD Col12 Col13 Col14 Col15 Col16 BSCC DPH AGR DWR CEC CA SL SLC Adopting Agency BSC BSC-
CGT-24 T-19* 1 2 1/AC AC SS 1 1R 2 3 4 5 5 5 5 5 5 5 5 5 Adopt Entire Chapter Adopt Entire Chapter as
amended (amended sections
listed below)X Adopt only those sections that
are listed below[California Code of Regulations,
Title 19, Division 1]Chapter / Section 301.1 X 301.2 X 302.1 X 302.2 X CWUIC § 6-1 High relevance — show source text
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 6-1
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6-2 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
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6 FIRE PROTECTION REQUIREMENTS
User notes:
About this chapter: In addition to the building construction requirements in the California Building Code and California Residential Code, this chapter contains requirements for development and construction in Local Responsibility Areas (LRA) designated as Very High Fire Hazard Severity Zones and areas designated by the State Fire Marshal as State Responsibility Areas (SRA). While many of these provisions are found in Title 14 and Title 19 of the California Code of Regulations, they are replicated here for the code user. The local jurisdiction has the authority to apply the same regulations to LRA when the regulations are adopted by local ordinance.
The requirements in this chapter reference the process for adoption of Very High Fire Hazard Severity Zones in the LRA; criteria for evaluating existing subdivisions that are at significant fire risk and are without an adequate secondary egress; and criteria for fire safety provisions required in the Safety Element of a city or county General Plan.
The chapter includes mitigation strategies to reduce the hazards of fire originating within a structure spreading to wildland and fire originating in wildland spreading to structures. These strategies are included in the following requirements:
1. Development of fire protection plans.
2. Development of landscape plans and long-term vegetation management.
3. Creation and maintenance of defensible space to protect structures and subdivisions.
SECTION 601—GENERAL
601.1 Scope. The provisions of this chapter establish general requirements for new and existing buildings, structures and premises located within wildland-urban interface (WUI) areas .
601.2 Objective. The objective of this chapter is to establish minimum requirements to mitigate conditions that might cause a fire originating in a structure to ignite vegetation in the wildland-urban interface (WUI) area, and conversely, a wildfire burning in vegetative fuels to transmit fire to buildings and threaten to destroy life, overwhelm fire suppression capabilities or result in large property losses.
601.3 Chapter 6 definitions. Where used in this chapter, the term listed below shall be defined as follows:
DEFENSIBLE SPACE. The buffer that landowners are required to create on their property between a “Building or Structure” and the plants, brush and trees or other items surrounding the “Building or Structure” that could ignite in the event of a fire. [CCR Title 14 §1299.02(a)]
SECTION 602— FIRE PROTECTION PLANS
602.1 General. The code official is authorized to require the owner or owner’s authorized agent to provide a fire protection plan. The fire protection plan shall be prepared to determine the acceptability of fire protection and life safety measures designed to mitigate wildfire hazards presented for the property under consideration.
The fire protection plan shall be prepared by a registered design professional, qualified landscape architect, qualified fire safety specialist or similar specialist acceptable to the code official and shall analyze the wildfire risk of the building, project, premises or region to recommend necessary changes.
The code official is authorized to require a preliminary fire protection plan prior to the submission of a final fire protection plan.
Frequently asked questions
Who actually decides whether my property is in a Fire Hazard Severity Zone?
The State Fire Marshal prepares and adopts the Fire Hazard Severity Zone maps and assigns ratings; local agencies then adopt ordinances based on those recommendations and may expand designations in their jurisdiction with required findings. See § 302.1 and the Government Code cross‑references reproduced in the CWUIC.
How often are the zones reviewed or changed?
The CWUIC directs reevaluation on a 5‑year basis (or sooner if needed) — see § 302.2. Changes to State maps/ratings follow State notice/hearing rules; local agencies have their own timelines described in the statutes referenced by the CWUIC.
Does § 302.1 list exact slope or fuel thresholds for each zone?
No. § 302.1 requires classification based on fuel loading, slope, fire weather, winds and other factors, but it does not contain numeric cutoffs in the CWUIC text returned here. The State Fire Marshal’s adopted mapping criteria and regulations provide the technical thresholds used to create the official maps.
Can my city make an area less severe than the State map shows?
No — a local agency may not decrease the level of fire hazard severity assigned by the State for any area; it may only increase the level with appropriate findings and procedures. See the Government Code language reproduced in the CWUIC (e.g., § 51179).
Where can I view the official maps?
The CWUIC references the official SRA Fire Hazard Severity Zone map filed by the Office of the State Fire Marshal (Title 19 reference). The OSFM posts maps on its website and the official map is on file with the State — see Appendix H references in the CWUIC.
More in California Wildland-Urban Interface Code
- Administration and Definitions
- Board of Appeals, Administration & Enforcement (permits, code official duties, appeals process)
- Wildland‑Urban Interface Area Designation & Mapping
- Fire Service Access & Water Supply (fire apparatus roads, driveways, hydrants, draft sites, standby power)
- Wildland‑Urban Interface Area Requirements (access, water, premises identification, key boxes)
- Referenced Standards & Test Methods
- Special Building Construction Regulations (ignition‑resistant construction, roof/vent/assembly requirements)
- Appendices and Model Ordinances (vegetation plans, severity‑zone adoption, home‑hardening guidance)
- Fire Protection Requirements (fire protection plans, systems, safety element provisions)
- Referenced California Documents & Matrix (CCR/Title 14 & 19 cross‑references, statutory references)
- Vegetation Management & Defensible Space (vegetation plans, maintenance, fire‑smart characteristics)
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