CWUIC · California Wildland-Urban Interface Code
What criteria are used to map and classify WUI areas?
The State Fire Marshal must map and classify lands into Fire Hazard Severity Zones by grouping relatively homogeneous lands and using factors like fuel loading, slope, fire weather and identified wind corridors; the section provides qualitative factors (not numeric cutoffs) and refers mapping procedures for SRAs and LRAs to the applicable state statutes via § 302.1.
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
The State Fire Marshal must classify lands into Fire Hazard Severity Zones and map WUI areas. The classification must assign each zone to reflect the expected severity of fire hazard, and zones must "embrace relatively homogeneous lands" using factors such as fuel loading, slope, fire weather and other relevant considerations (including areas where winds have been identified as a major cause of wildfire spread and areas designated by the enforcing agency) — see § 302.1. § 302.1 also ties the mapping process to the statutory mapping procedures for State Responsibility Areas and Local Responsibility Areas. § 302.1
The map must group relatively similar lands and label them by expected fire hazard severity — using fuel, slope, weather (including wind corridors) and other relevant local factors — so the State Fire Marshal and enforcing agencies can assign Fire Hazard Severity Zones. § 302.1
Requirements in detail
Key defined terms and first mentions (bolded): § 302.1, Fire Hazard Severity Zones, State Fire Marshal, State Responsibility Areas (SRA), Local Responsibility Areas (LRA), fuel loading, slope, fire weather, winds, homogeneous lands, enforcing agency. These come directly from § 302.1.
What must be done
- Classify lands into Fire Hazard Severity Zones (this is the mapping product required by the Code). § 302.1
- Base each zone assignment on the severity of fire hazard expected to prevail. § 302.1
- Ensure each zone "embrace[s] relatively homogeneous lands" — grouping areas with similar hazard characteristics. § 302.1
- Use fuel loading, slope, fire weather, and other relevant factors (explicitly including areas where winds have been identified by the Office of the State Fire Marshal as major drivers of spread and other areas designated by the enforcing agency) when classifying. § 302.1
- For procedural authority and the statutory scheme, the State Fire Marshal shall classify SRA lands in accordance with PRC §§ 4201–4204 and LRA lands in accordance with Gov. Code §§ 51175–51189, as referenced in § 302.1. § 302.1
Decision-relevant dimensions (quick table)
| Dimension / value examined | How it affects the zone decision | Code reference |
|---|---|---|
| Fuel loading (quantity/type of vegetation) | Higher fuel loads increase expected fire intensity and likelihood of spread → tends toward higher-severity zones | § 302.1 |
| Slope (steepness) | Steeper slopes increase rate of uphill fire spread → influences higher severity classification | § 302.1 |
| Fire weather (temperature, humidity, drought, fire-weather indices) | More extreme fire weather raises expected hazard and may push an area into a higher severity zone | § 302.1 |
| Winds / wind corridors | Areas identified by OSFM where wind is a major cause of spread are specifically called out as relevant | § 302.1 |
| Homogeneity (grouping similar lands) | Zones must "embrace relatively homogeneous lands" — mapping should avoid highly mixed zones without justification | § 302.1 |
| Jurisdictional mapping procedure | SRA mapped per PRC §§ 4201–4204; LRA mapped per Gov. Code §§ 51175–51189 — statutory mapping process controls who and how | § 302.1 |
Notes on the table: § 302.1 sets the qualitative factors; it does not itself specify numeric cutoffs (e.g., exact slope % or fuel tons/acre) in the text of § 302.1. The mapping follows the referenced statutes and any implementing OSFM methods. § 302.1
Exceptions & special cases
- The Code text of § 302.1 does not include explicit numeric thresholds, prescriptive measurement methods, or a fixed set of zone labels (it is qualitative and delegates mapping procedures to the State Fire Marshal and the statutory authorities for SRA and LRA). If you need numeric breakpoints or a GIS workflow, those come from the State Fire Marshal’s mapping procedures, referenced statutes (PRC/Gov. Code), or local implementing ordinances — § 302.1 .
- The clause "other relevant factors" and "other areas designated by the enforcing agency" means local circumstances (e.g., proximity to urban fuels, infrastructure, or special wind patterns) can be brought into the mapping decision; these are not limited by the Code text in § 302.1. § 302.1 .
- Mapping for State Responsibility Areas (SRA) and Local Responsibility Areas (LRA) follows different statutory pathways (PRC vs Gov. Code) even though the same factors apply; consult the statutory mapping documents for procedure and appeals. § 302.1 .
Common mistakes
- Treating § 302.1 as a source of numeric thresholds (e.g., "slope above X% = Very High") — the section lists qualitative factors but does not set numeric breakpoints. § 302.1 .
- Ignoring winds and OSFM-identified wind corridors — § 302.1 specifically calls out winds as a factor the Office of the State Fire Marshal may identify as a major cause of spread. § 302.1 .
- Mapping parcels in isolation instead of grouping relatively homogeneous lands — failing to create zones that reflect area-wide hazard patterns defeats the intent of § 302.1. § 302.1 .
- Assuming a single agency’s map is final for both SRA and LRA — the section ties classification to PRC and Government Code procedures, which differ by responsibility area. § 302.1 .
Worked example — applying the rule (concrete scenario)
Scenario inputs (sample values used only for applying the described factors, not taken as Code thresholds):
- Parcel A: 40 acres; average slope = 30%; fuel loading = heavy (dense chaparral/shrub); location lies within an OSFM-identified wind corridor; recent fire-weather indices show frequent red-flag conditions.
Applying § 302.1:
- The mapper (State Fire Marshal or enforcing agency) evaluates fuel loading (heavy) and slope (30%) and fire weather (frequent extreme conditions). These inputs indicate a higher expected fire severity per the qualitative factors in § 302.1. § 302.1 .
- Because the parcel is in a mapped wind corridor identified by OSFM, that factor explicitly supports assigning a higher hazard zone. § 302.1 .
- The mapper checks surrounding lands: if adjoining parcels are similar (homogeneous fuels/topography), the zone should be drawn to embrace that homogeneous area rather than parcel-by-parcel fragmentation. § 302.1 .
- Final result (procedural outcome, not a statutory number): Parcel A would likely be placed in a higher Fire Hazard Severity Zone (e.g., Very High) on the map because the combination of heavy fuels, steep slope, adverse fire weather, and identified wind-driven spread increases expected severity — consistent with the classification factors named in § 302.1. § 302.1 .
Important caveat: § 302.1 does not supply a table that says "30% slope = X zone." The example uses measurable inputs to illustrate how the qualitative criteria in § 302.1 are applied by the mapping authority. § 302.1
Related provisions
- § 302.2 — Review of wildland‑urban interface areas (periodic reevaluation and modification process). § 302.2
- § 301.2 — Purpose for classifying lands by level of fire hazard (context for mapping). § 301.2
- PRC and Government Code mapping authority referenced in § 302.1: PRC §§ 4201–4204 (State Responsibility Areas) and Gov. Code §§ 51175–51189 (Local Responsibility Areas) — see § 302.1 for the statutory tie-in. § 302.1
- Fire protection planning and project-level wildfire assessment (examples of documents that use WUI maps): § 602.2 (contents of a fire protection plan) — maps and fuel modification zones are incorporated into project reviews. § 602.2
Code references
Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:
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 § 302.1 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 § 1-2 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 § 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 § 102.4 High relevance — show source text
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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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.
Chapter 7 Referenced Standards.
Chapter 7 lists all of the product and installation standards and codes that are referenced throughout Chapters 1 through 6 and includes identification of the promulgators and the section numbers in which the standards and codes are referenced. As stated in Section 102.4, these standards and codes become an enforceable part of the code (to the prescribed extent of the reference) as if printed in the body of the code.
Appendix A General Requirements.
Appendix A, while not part of the code, can become part of the code when specifically included in the adopting ordinance. Its purpose is to provide fire-protection measures supplemental to those found in Chapter 6 to reduce the threat of wildfire in a wildland-urban interface area and improve the capability for controlling such fires. This appendix includes detailed requirements for vegetation control; the code official’s authority to close wildland-interface areas in times of high fire danger; control of fires, fireworks usage and other sources of ignition; storage of hazardous materials and combustibles; bans on the dumping of waste materials and ashes and coals in wildlandurban interface areas; protection of pumps and water supplies; and limits on temporary uses within the wildland-urban interface area.
Appendix B Vegetation Management Plan.
Appendix B, while not part of the code, can become part of the code when specifically included in the adopting ordinance. Its purpose is to provide criteria for submitting vegetation management plans, specifying their content and establishing a criterion for considering vegetation management as being a fuel modification.
Appendix C Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework.
CWUIC § 601.1 High relevance — show source text
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.
602.2 Contents. The fire protection plan shall be based on a project-specific wildfire hazard assessment that includes considerations of location, topography, aspect and climatic and fire history.
The plan shall identify conformance with all applicable state wildfire protection regulations, statutes and applicable local ordi- nances, whichever are more restrictive.
The plan shall address fire department access, egress, road and address signage and water supply in addition to fuel reduction in accordance with Public Resources Code (PRC) 4290; the defensible space requirements in accordance with PRC 4291 or Government Code 51182; and the applicable building codes and standards for wildfire safety. The plan shall identify mitigation measures to address the project’s specific wildfire risk and shall include the information required in Sections 602.3 through 602.3.2.
602.3 Project information. The final fire protection plan shall be reviewed and approved prior to start of construction.
602.3.1 Preliminary fire protection plan. When a preliminary fire protection plan is submitted, it shall include, at a minimum, the following: 1. Total size of the project. 2. Information on the adjoining properties on all sides, including current land uses, and if known, existing structures and densi- ties, planned construction, natural vegetation, environmental restoration plans, roads and parks. 3. A map with all project boundary lines, property lines, slope contour lines, proposed structure foundation footprints, and proposed roads and driveways. The map shall identify project fuel modification zones and method of identifying the fuel modification zone boundaries.
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CWUIC § 102.4 High relevance — show source text
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.
Chapter 7 Referenced Standards.
Chapter 7 lists all of the product and installation standards and codes that are referenced throughout Chapters 1 through 6 and includes identification of the promulgators and the section numbers in which the standards and codes are referenced. As stated in Section 102.4, these standards and codes become an enforceable part of the code (to the prescribed extent of the reference) as if printed in the body of the code.
Appendix A General Requirements.
Appendix A, while not part of the code, can become part of the code when specifically included in the adopting ordinance. Its purpose is to provide fire-protection measures supplemental to those found in Chapter 6 to reduce the threat of wildfire in a wildland-urban interface area and improve the capability for controlling such fires. This appendix includes detailed requirements for vegetation control; the code official’s authority to close wildland-interface areas in times of high fire danger; control of fires, fireworks usage and other sources of ignition; storage of hazardous materials and combustibles; bans on the dumping of waste materials and ashes and coals in wildlandurban interface areas; protection of pumps and water supplies; and limits on temporary uses within the wildland-urban interface area.
Appendix B Vegetation Management Plan.
Appendix B, while not part of the code, can become part of the code when specifically included in the adopting ordinance. Its purpose is to provide criteria for submitting vegetation management plans, specifying their content and establishing a criterion for considering vegetation management as being a fuel modification.
Appendix C Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework.
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.
**App
CWUIC § 302.1 Medium relevance — show source text
2|Purpose|Y|||||||51176|4201| |302|Wildland-Urban
Interface Area
Designations|Y||||||||| |302.1|Mapping|Y|||4904.2||||51178|4202
4203(a)
4204| |302.2|Review of wildland-
urban interface areas|Y|||||||51181|4204| |Chapter 4|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements| |401|General|Y||||||||| |401.1|Scope|Y||||||||| |401.2|Objective|Y||||1273.00||||| |401.3|General safety
precautions|Y||||||||| |402|Applicability|Y|||||||||APPENDIX H-26 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
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APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS
2025 CWUIC—continued Col2 Adopted
Yes/NoIWUIC
SectionCBC
SectionCFC
SectionTitle 14,
Division 1.5
SectionTitle 19,
Division 1
SectionGov Code
SectionPRC
SectionHSC
SectionSection Title Title Title Title Title Title Title Title Title Title Chapter 4 Wildland-urban interface area requirements Wildland-urban interface area requirements Wildland-urban interface area requirements Wildland-urban interface area requirements Wildland-urban interface area requirements Wildland-urban interface area requirements Wildland-urban interface area requirements Wildland-urban interface area requirements Wildland-urban interface area requirements Wildland-urban interface area requirements 402.1 Subdivisions Y 402.1.1 Access Y 503 402.1.2 Water supply Y 507 402.1.2.1 Parcel map approval Y 1275.01 402.2 Individual structures Y 503
507402.2.1 Access Y 503 402.2.2 Water supply Y 507 402.3 Existing conditions N 505.1 403 Access Y 1273 403.1 General Y 1273.00 403.1.1 Section 403 definitions Y 1270.01(f) 403.1.2 Width Y 1273.01(a)
1273.CWUIC § 1-2 Medium relevance — show source text
Population growth and the expanding urban development into traditionally nonurban areas have increasingly brought humans into contact with wildfires. According to the National Fire Protection Agency (NFPA), every year, wildfires burn across the United States and a growing number of people are living where wildfires are a real risk. In 2018 more than 58,000 fires burned nearly 9 million acres across the US. More than 25,000 structures were destroyed, including 18,137 residences and 229 commercial structures. California accounted for the highest number of structures lost in one state due to the number of significant fires, including the Mendocino Complex, Carr, Camp and Woolsey fires.
The IWUIC is a model code that is intended to be adopted and used supplemental to the adopted building and fire codes of a jurisdiction. The unrestricted use of property in wildland-urban interface areas is a potential threat to life and property from fire and resulting erosion. The IWUIC has as its objective the establishment of minimum special regulations for the safeguarding of life and
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property from the intrusion of fire from wildland fire exposures and fire exposures from adjacent structures and to prevent structure fires from spreading to wildland fuels, even in the absence of fire department intervention.
Safeguards to prevent the occurrence of fires and to provide adequate fire protection facilities to control the spread of fire in wildland-urban interface areas are provided in a tiered manner commensurate with the relative level of hazard present.
ARRANGEMENT AND FORMAT OF THE 2025 CWUIC
The format of the CWUIC allows each chapter to be devoted to a particular subject. The following table shows how the CWUIC is divided. The chapter synopses detail the scope and intent of the provisions of the CWUIC.
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.
CWUIC § 4.1 Medium relevance — show source text
4|Combustible
materials|N||||||||| |A105.4.1|Individual piles|N||||||||| |A105.4.2|Separation|N||||||||| |A106|Dumping|N||||||||| |A106.1|Waste material|N||||||||| |A106.2|Ashes and coals|N||||||||| |A107|Protection of pumps
and water storage
facilities|N||||||||| |A107.1|General|N||||||||| |A107.2|Objective|N||||||||| |A107.3|Fuel modification
area|N||||||||| |A107.4|Trees|N||||||||| |A107.5|Protection of electri-
cal power supplies|N||||||||| |A108|Land use limitations|N||||||||| |A108.1|General|N||||||||| |A108.2|Objective|N||||||||| |A108.3|Permits|N||||||||| |A108.4|Access roadways|N||||||||| |A109|Referenced standards|N||||||||| |A109.1|General|N|||||||||APPENDIX H-34 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
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APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS
2025 CWUIC—continued Col2 Adopted
Yes/NoIWUIC
SectionCBC
SectionCFC
SectionTitle 14,
Division 1.5
SectionTitle 19,
Division 1
SectionGov Code
SectionPRC
SectionHSC
SectionSection Title Title Title Title Title Title Title Title Title Title Appendix B Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan B101 General N B101.1 Scope N B101.2 Plan content N B101.3 Fuel modification N Appendix C Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework **_Community Wildland-Urban Interface (WUI) CWUIC § 4911 Medium relevance — show source text
1|Scope|N||||||||| |B101.2|Plan content|N||||||||| |B101.3|Fuel modification|N||||||||| |Appendix C|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework|Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework| |C101|Community WUI Fire
Hazard Evaluation
Framework|N|||Appendix
P|||||| |C101.1|Definitions|N||||||||| |C101.2|Community|N||||||||| |C101.3|Fuels|N||||||||| |C101.4|Population|N||||||||| |C101.5|Notification|N||||||||| |C101.6|Evacuation|N||||||||| |C101.7|Infrastructure/
COOP/COG|N||||||||| |C101.8|Firefighting Response|N||||||||| |Appendix D|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption|Model Ordinance for Fire Hazard Severity Zone Adoption| |D101|Model ordinance|N|||4911|||||| |Appendix E|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED|RESERVED| |Appendix F|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation|Characteristics offire-smart vegetation| |F101|General|Y||||||||| |F101.CWUIC § 301.1 Medium relevance — show source text
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 - The California Code of Regulations (CCR), Title 19, Division 1 provisions that are found in the California Wildland-Urban Interface Code are a reprint from the current CCR, Title 19, Division 1 text for the code user’s convenience only. The scope, applicability and appeals procedures of CCR, Title 19, Division I remain the same. The state agency does not adopt sections identified by the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
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.
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 3-1
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3-2 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
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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
Frequently asked questions
Who makes the final zone map?
The State Fire Marshal is charged with classifying lands into Fire Hazard Severity Zones; the mapping for SRAs and LRAs follows the statutory procedures referenced in § 302.1. § 302.1
Does § 302.1 give slope or fuel thresholds?
No. § 302.1 lists fuel loading, slope, fire weather, winds and other factors to be used qualitatively; it does not provide numeric thresholds or cutoffs. § 302.1
Can a local enforcing agency add other factors?
Yes — § 302.1 explicitly permits "other relevant factors" and areas designated by the enforcing agency to be considered in classification. § 302.1
How often are maps reviewed or updated?
The mapping review schedule is addressed in the Code’s companion provision § 302.2, which requires periodic reevaluation (see that section for the review cadence). § 302.2
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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