CWUIC · California Wildland-Urban Interface Code
What water supply and fire-flow are required for structures in WUI areas?
If you build in a WUI area you must have an approved water supply that can deliver the fire‑flow needed to protect the house and address wildland exposure. The CWUIC (especially **§ 404.1**, **§ 404.2**, **§ 404.5**) states the water supply must be “capable of supplying the required fire flow” and directs you to use the California Fire Code Appendix B/BB to calculate the actual gallons‑per‑minute and duration; if you rely on tanks, ponds or draft sites those must be approved and accessible to fire apparatus.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
The California Wildland‑Urban Interface Code requires an approved water source adequate for firefighting to protect buildings from wildland exposure and to suppress structure fires — see § 404.1 . The premises must be supplied with an approved water supply capable of supplying the required fire flow in accordance with § 404.2 and Section 507 of the California Fire Code (fire‑flow sizing and duration) . The method for determining the actual fire‑flow is to use the California Fire Code Appendix B (or BB) as referenced in § 404.5 .
The single most important rule: provide an approved water supply that can deliver the fire‑flow determined under the California Fire Code Appendix B to the property (CWUIC § 404.2 / § 404.5) .
Requirements in detail
High‑level duties (plain language)
- The jurisdiction must ensure there is an approved water source for fire protection in WUI areas (§ 404.1) .
- New or relocated buildings must have water service that is capable of supplying the required fire flow for both structural protection and wildland exposure (§ 404.2) .
- The required fire‑flow and duration are not calculated in CWUIC text; they are to be determined “in accordance with Appendix B or BB of the California Fire Code” (CWUIC § 404.5) .
Decision‑relevant table
| Decision element | What to check / value to determine | Code Reference |
|---|---|---|
| Need for an approved water source | Is there an approved water source available and maintained for fire protection on the premises? | § 404.1 |
| Premises supply capability | Is the on‑site supply capable of supplying the required fire flow (gpm and duration) to the premises? | § 404.2 |
| How to calculate the gpm & duration | Use the California Fire Code Appendix B (or BB) method and tables to determine required fire‑flow and flow duration | § 404.5 and California Fire Code Appendix B |
| Hydrant number / spacing | Hydrant number/spacing is to follow the California Fire Code Appendix C/CC (referenced by CWUIC § 404.4) — verify local application | § 404.4 |
| Draft / pumper access | If using natural water sources, provide approved draft sites and pumper access as required (see § 404.3 for design & pumper access limits) | § 404.3 / § 404.3.2 |
(Notes: CWUIC gives the performance requirement — have a water supply able to deliver the fire‑flow — and points you to the California Fire Code for the calculation tables and methods. The CWUIC sections above are the controlling text for WUI water‑supply intent and connection to the Fire Code.)
What “required fire flow” means here
- Required fire flow is the flow rate and duration necessary to protect the building(s) from structure fire and nearby wildland exposure; the CWUIC does not list gpm values but directs users to the California Fire Code Appendix B/BB to determine the numeric requirement (§ 404.5) .
- Calculation inputs include the building’s fire‑flow calculation area and construction type per the California Fire Code (see Appendix B guidance) .
Exceptions & special cases
- The CWUIC ties sizing to the California Fire Code, which itself authorizes the fire‑code official to reduce fire‑flow requirements for isolated buildings or rural communities where full fire‑flow is impractical (Appendix B, B103.1) — consult the local fire‑code official for authorized reductions .
- Where there is no municipal distribution system, compliance may rely on draft sites at natural water sources, reservoirs, or other approved supplies; those draft sites and pumper access must meet CWUIC requirements (see § 404.3) .
- CWUIC § 404.2 expressly ties premises requirements to Section 507 of the California Fire Code — where alternate methods (standpipes, on‑site reservoirs, private hydrants, etc.) are permitted those will be controlled by the Fire Code and the local authority having jurisdiction (AHJ) .
Common mistakes
- Assuming CWUIC itself prescribes a universal gpm figure. CWUIC requires an approved source capable of the required flow but refers you to the California Fire Code Appendix B/BB for the actual gpm/duration — do not skip that step (§ 404.2, § 404.5) .
- Designing on‑site supply without confirming whether the AHJ will accept reductions for remote or rural sites (Appendix B reductions are discretionary) .
- Forgetting draft‑site and pumper access details when relying on natural sources — CWUIC requires approved draft sites and pumper access be provided and accessible (§ 404.3, § 404.3.2) .
- Overlooking hydrant location/spacing and identification rules referenced elsewhere in Chapter 4 (hydrants must meet national standards; number/spacing per Appendix C/CC) rather than assuming any hydrant meets WUI needs (§ 404.4) .
Worked example — how to apply the rule (process with numbers you must lookup)
This example shows the required process using a concrete project; I cannot invent the Appendix B table values from the code text you provided, so the final gpm must be taken from Appendix B or from your local AHJ.
Scenario: a proposed new single‑family wood‑frame house, total floor area 3,000 ft², located in a designated WUI area.
Step 1 — determine the fire‑flow calculation area:
- Use California Fire Code Appendix B rules (B104.1) to calculate the fire‑flow calculation area (total floor area under exterior walls and roof projections) .
Step 2 — find the required fire‑flow and duration:
- Consult Appendix B (tables B105.1(1) or applicable table for one‑ and two‑family dwellings) to identify the required fire‑flow (gpm) and duration (minutes) for the calculated area and construction type. I do not have the numeric table text in the CWUIC files provided here, so obtain the table from the California Fire Code Appendix B or ask the AHJ for the value .
Step 3 — confirm supply capability to the premises:
- Verify the property’s on‑site or distribution system can deliver that gpm at the necessary residual pressure and for the required duration to the building location. If the property cannot, identify approved alternatives (e.g., private tank + pump, reservoir, draft site with pumper access) in coordination with the AHJ as required by § 404.2 and § 404.1 .
Step 4 — meet CWUIC access/implementation details:
- If using a draft site, ensure pumper access and site details conform to CWUIC draft‑site provisions and pumper access distances (see § 404.3 / § 404.3.2) .
- Provide hydrants or fire department connections as required by the Fire Code strategy used to meet the required fire‑flow, and mark/identify water sources per CWUIC § 404.8 if applicable .
If you want, I can fetch the precise gpm/duration table entries from Appendix B and run the arithmetic for this 3,000 ft² example — tell me whether to pull the California Fire Code Appendix B table now.
Related provisions
- § 404.1 — General requirement for an approved water source for WUI protection
- § 404.2 — Required water supply capable of supplying the required fire flow; ties to California Fire Code Section 507
- § 404.3 — Draft sites and pumper access requirements for natural water sources
- § 404.4 — Hydrants design, construction, and spacing (Appendix C/CC reference)
- § 404.5 — Directs use of California Fire Code Appendix B/BB for fire‑flow determination
- California Fire Code — Appendix B (Fire‑Flow Requirements for Buildings): method and tables to calculate gpm and duration (referenced by CWUIC § 404.5)
Code references
Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:
CWUIC § 1274.04 High relevance — show source text
or otherwise posted to provide for unobstructed visibility from that_ intersection.
(f) In all cases, the address shall be posted at the beginning of construction and shall be maintained thereafter.
[CCR, Title 14 §1274.04]
SECTION 404—WATER SUPPLY
404.1 General. An approved water source shall have an adequate water supply for the use of the fire protection service to protect buildings and structures from exterior fire sources or to suppress structure fires within the wildland-urban interface area of the jurisdiction in accordance with this section.
404.2 Required water supply. An approved water supply capable of supplying the required fire flow for structural fire protection and wildland fire exposure shall be provided to the premises on which facilities, buildings or portions of buildings are hereafter constructed or moved into or within the jurisdiction in accordance with Section 507 of the California Fire Code.
404.3 Draft sites. Approved draft sites shall be provided at natural water sources intended for use as fire protection for compliance with this code. The design, construction, location, access and access maintenance of draft sites shall be approved by the code official.
404.3.1 Access. The draft site shall have emergency vehicle access from an access road in accordance with Section 403.
404.3.2 Pumper access points. The pumper access point shall be either an emergency vehicle access area alongside a conforming access road or an approved driveway not longer than 150 feet (45 720 mm). Pumper access points and access driveways shall be designed and constructed in accordance with all codes and ordinances enforced by this jurisdiction. Pumper access points shall not require the pumper apparatus to obstruct a road or driveway.
404.4 Hydrants. Hydrants shall be designed and constructed in accordance with nationally recognized standards. The location and access shall be approved by the code official. The number and spacing of fire hydrants shall be in accordance with Appendix C or CC of the California Fire Code, as applicable.
404.5 Adequate water supply. Fire-flow requirements shall be determined in accordance with Appendix B or BB of the California Fire Code, as applicable.
404.6 Reserved.
404.7 Obstructions. Access to water sources required by this code shall be unobstructed at all times. The fire department shall not be deterred or hindered from gaining immediate access to water source equipment, fire protection equipment or hydrants.
404.8 Identification. Water sources, draft sites, hydrants and fire protection equipment and hydrants shall be clearly identified in a manner approved by the code official to identify location and to prevent obstruction by parking and other obstructions. Each fire hydrant and access to a water supply shall be identified in accordance with one of the following: 1. Where located along a driveway, a reflectorized blue marker with a minimum dimension of 3 inches (73 mm) shall be located on the driveway address sign and mounted on a fire-retardant post. 2. Where located along an access road: 2.2. A reflectorized blue marker with a minimum dimension of 3 inches (73 mm) shall be mounted on a fire-retardant post. The signpost shall be within 3 feet (914 mm) of said fire hydrant with the sign not less than 3 feet (914 mm) nor greater than 5 feet (1524 mm) above ground, in a horizontal position and visible from the driveway. _2.3.
CWUIC § 1274.02 High relevance — show source text
[CCR, Title 14 §1274.02]
403.2.4 Addresses for Buildings. (a) All Buildings shall be issued an address by the Local Jurisdiction which conforms to that jurisdiction's overall address system. Utility and miscellaneous Group U Buildings are not required to have a separate address; however, each Residential Unit within a Building shall be separately identified. (b) The size of letters, numbers and symbols for addresses shall conform to the standards in the California Fire Code, California Code of Regulations Title 24, Part 9. (c) Addresses for residential Buildings shall be reflectorized.
[CCR, Title 14 §1274.03]
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WILDLAND-URBAN INTERFACE AREA REQUIREMENTS
403.2.5 Address installation, location and visibility. (a) All buildings shall have a permanently posted address which shall be plainly legible and visible from the Road fronting the property. (b) Where access is by means of a private Road and the address identification cannot be viewed from the public way, an unob- structed sign or other means shall be used so that the address is visible from the public way. (c) Address signs along one-way Roads shall be visible from both directions. (d) Where multiple addresses are required at a single driveway, they shall be mounted on a single sign or post. (e) Where a Road provides access solely to a single commercial or industrial business, the address sign shall be placed at the near- est Road intersection providing access to that site, or otherwise posted to provide for unobstructed visibility from that intersection.
(f) In all cases, the address shall be posted at the beginning of construction and shall be maintained thereafter.
[CCR, Title 14 §1274.04]
SECTION 404—WATER SUPPLY
404.1 General. An approved water source shall have an adequate water supply for the use of the fire protection service to protect buildings and structures from exterior fire sources or to suppress structure fires within the wildland-urban interface area of the jurisdiction in accordance with this section.
404.2 Required water supply. An approved water supply capable of supplying the required fire flow for structural fire protection and wildland fire exposure shall be provided to the premises on which facilities, buildings or portions of buildings are hereafter constructed or moved into or within the jurisdiction in accordance with Section 507 of the California Fire Code.
404.3 Draft sites. Approved draft sites shall be provided at natural water sources intended for use as fire protection for compliance with this code. The design, construction, location, access and access maintenance of draft sites shall be approved by the code official.
404.3.1 Access. The draft site shall have emergency vehicle access from an access road in accordance with Section 403.
404.3.2 Pumper access points. The pumper access point shall be either an emergency vehicle access area alongside a conforming access road or an approved driveway not longer than 150 feet (45 720 mm). Pumper access points and access driveways shall be designed and constructed in accordance with all codes and ordinances enforced by this jurisdiction. Pumper access points shall not require the pumper apparatus to obstruct a road or driveway.
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 § 4-1 High relevance — show source text
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4 WILDLAND-URBAN INTERFACE AREA REQUIREMENTS
User notes:
About this chapter: Chapter 4 provides requirements that 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.
SECTION 401—GENERAL
401.1 Scope. Wildland-urban interface areas shall be provided with emergency vehicle access and water supply in accordance with this chapter.
401.2 Objective. The objective of this chapter is to establish the minimum requirements for emergency vehicle access and water supply for buildings and structures located in the wildland-urban interface areas.
401.3 General safety precautions. General safety precautions shall be in accordance with this chapter. See also Appendix A.
SECTION 402—APPLICABILITY
402.1 Subdivisions. Subdivisions shall comply with Sections 402.1.1 and 402.1.2.
402.1.1 Access. New subdivisions, as determined by this jurisdiction, shall be provided with fire apparatus access roads in accordance with the California Fire Code; the California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 2, Article 2; and access requirements in accordance with Section 403.
402.1.2 Water supply. New subdivisions as determined by this jurisdiction shall be provided with water supply in accordance with Section 507 of the California Fire Code; California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 2, Article 4; and Section 404.
402.1.2.1 Parcel map approval. Water supply requirements shall apply in the tentative and parcel map process when new parcels are approved by the local jurisdiction.
402.2 Individual structures. Individual structures shall comply with Sections 402.2.1 and 402.2.2.
402.2.1 Access. Individual structures hereafter constructed or relocated into or within wildland-urban interface areas shall be provided with fire apparatus access in accordance with the California Fire Code; the California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 2, Subsection 1273; and Section 403 .
402.2.2 Water supply. Individual structures hereafter constructed or relocated into or within wildland-urban interface areas shall be provided with a conforming water supply in accordance with the California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 2, Article 4; California Fire Code Section 507; and Section 404.
CWUIC § 1512.3.1 High relevance — show source text
[F] 1512.3.1 Fire separation up to 30 feet. Where a building of Type III, IV or V construction has a fire separation distance of less than 30 feet (9144 mm) from property lot lines, and an adjacent property has an existing structure or otherwise can be built on, the water supply shall provide either a minimum of 500 gallons per minute (1893 L/m), or the entire fire flow required for the building when constructed, whichever is greater.
[F] 1512.3.2 Fire separation of 30 feet up to 60 feet. Where a building of Type III, IV or V construction has a fire separation distance of 30 feet (9144 mm) up to 60 feet (18 288 mm) from property lot lines, and an adjacent property has an existing structure or otherwise can be constructed upon, the water supply shall provide a minimum of 500 gallons per minute (1893 L/m), or 50 percent of the fire flow required for the building when constructed, whichever is greater.
[F] 1512.3.3 Fire separation of 60 feet or greater. Where a building of Type III, IV or V construction has a fire separation of 60 feet (18 288 mm) or greater from a property lot line, a water supply of 500 gallons per minute (1893 L/m) shall be provided.
[F] 1512.4 Vertical construction, Types I and II construction. If combustible construction materials are delivered to the construction site, water supply in accordance with Section 1509.2 shall be provided. Additional water supply for fire flow is not required prior to commencing vertical construction of Type I and II buildings.
[F] 1512.5 Standpipe supply. Regardless of the presence of combustible building materials, the construction type or the fire separation distance, where a standpipe is required in accordance with Section 1509, a water supply providing a minimum flow of 500 gallons per minute (1893 L/m) shall be provided. The fire hydrant used for this water supply shall be located within 100 feet (30 480 mm) of the fire department connection supplying the standpipe.
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CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE
CHAPTER 16 – REFERENCED STANDARDS
(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 HCD Col6 Col7 DSA Col9 Col10 OSHPD Col12 Col13 Col14 Col15 Col16 Col17 BSCC DPH AGR DWR CEC CA SL SLC Adopting 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 § 101.1 High relevance — show source text
PART 1—GENERAL PROVISIONS
SECTION 101—SCOPE AND GENERAL REQUIREMENTS
[A] 101.1 Title. These regulations shall be known as the California Wildland-Urban Interface Code of [ NAME OF JURISDICTION ], hereinafter referred to as “this code.”
[A] 101.2 Scope. This code applies to building materials, systems and/or assemblies used in the exterior design and construction of new buildings located within a wildland-urban interface (WUI) area and contains 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.
[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted.
[A] 101.3 Purpose. The purpose of this code is to establish minimum regulations for the safeguarding of life and for property protection. Regulations in this code are intended to mitigate the risk to life and structures from intrusion of fire from wildland fire exposures and fire exposures from adjacent structures and to mitigate structure fires from spreading to wildland fuels. The extent of this regulation is intended to be tiered commensurate with the relative level of hazard present.
The unrestricted use of property in wildland-urban interface areas is a potential threat to life and property from fire and resulting erosion. 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 shall be in accordance with this code.
This code shall supplement the jurisdiction’s building and fire codes, if such codes have been adopted, to provide for special regulations to mitigate the fire- and life-safety hazards of the wildland-urban interface areas.
101.3.1 Application. New buildings located in any Fire Hazard Severity Zone or Wildland-Urban Interface (WUI) Fire Area designated by the enforcing agency constructed after the application date shall comply with the provisions of this code. This shall include all new buildings with residential, commercial, educational, institutional or similar occupancy type use, which shall be referred to in this code as “applicable buildings,” as well as new buildings and structures accessory to those applicable buildings.
Exceptions: 1. Group U occupancy accessory buildings of any size located at least 50 feet (15 240 mm) from an applicable building on the same lot.
2. Group U occupancy agricultural buildings, as defined in Section 202 of the California Building Code of any size located at least 50 feet (15 240 mm) from an applicable building. 3. Group C occupancy special buildings conforming to the limitations specified in Section 450.4.1 of the California Building Code. 4. New accessory buildings and miscellaneous structures specified in Section 504.11 shall comply only with the requirements of that section.
5. Additions to and remodels of buildings originally constructed prior to July 1, 2008.
101.3.1.1 Application date and where required. New buildings for which an application for a building permit is submitted on or after July 1, 2008, located in any Fire Hazard Severity Zone or Wildland-Urban Interface Area shall comply with this code, including all of the following areas:
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 § 402.1.1 High relevance — show source text
402.1.1 Access. New subdivisions, as determined by this jurisdiction, shall be provided with fire apparatus access roads in accordance with the California Fire Code; the California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 2, Article 2; and access requirements in accordance with Section 403.
402.1.2 Water supply. New subdivisions as determined by this jurisdiction shall be provided with water supply in accordance with Section 507 of the California Fire Code; California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 2, Article 4; and Section 404.
402.1.2.1 Parcel map approval. Water supply requirements shall apply in the tentative and parcel map process when new parcels are approved by the local jurisdiction.
402.2 Individual structures. Individual structures shall comply with Sections 402.2.1 and 402.2.2.
402.2.1 Access. Individual structures hereafter constructed or relocated into or within wildland-urban interface areas shall be provided with fire apparatus access in accordance with the California Fire Code; the California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 2, Subsection 1273; and Section 403 .
402.2.2 Water supply. Individual structures hereafter constructed or relocated into or within wildland-urban interface areas shall be provided with a conforming water supply in accordance with the California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 2, Article 4; California Fire Code Section 507; and Section 404.
402.3 Existing conditions. Existing buildings shall be provided with address markers in accordance with Sections 403.2.4 and 403.2.5 . Existing roads and fire protection equipment shall be provided with markings in accordance with Sections 403.4 and 404.8, respectively.
SECTION 403—ACCESS
USER NOTE: The standards in Section 403 applicable to roads shall not apply to roads used solely for agriculture; mining; or the management of timberland or harvesting of forest products. [CCR, Title 14 §1270.03(d)]
403.1 General. Roads and driveways, whether public or private, unless exempted under 14 CCR § 1270.03(d), shall provide for safe access for emergency wildfire equipment and civilian evacuation concurrently, and shall provide unobstructed traffic circulation during a wildfire emergency consistent 403.1.1 to 403.1.9. [CCR, Title 14 §1273.00]
403.1.1 Section 403 definitions. When used in Section 403, the term listed below shall be defined as follows:
DEFENSIBLE SPACE. The area within the perimeter of a parcel, development, neighborhood or community where basic wildland fire protection practices and measures are implemented to defend against encroaching wildfire or to escape structure fires. The perimeter as used in this regulation [CCR Title 14] is the area encompassing the parcel or parcels proposed for construction and/or development, excluding the physical structure itself. The area is characterized by the establishment and maintenance of emer- gency vehicle access, emergency water reserves, road names and identification, and fuel modification measures. [CCR Title 14 §1270.01(f)]
CWUIC § 3313.2 High relevance — show source text
[F] 3313.2 Combustible building materials. When combustible building materials of the building under construction are delivered to a site, a minimum fire flow of 500 gallons per minute (1893 L/m) shall be provided. The fire hydrant used to provide this fire flow supply shall be within 500 feet (152 m) of the combustible building materials, as measured along an approved fire apparatus access lane. Where the site configuration is such that one fire hydrant cannot be located within 500 feet (152 m) of all combustible building materials, additional fire hydrants shall be required to provide coverage in accordance with this section.
[F] 3313.3 Vertical construction of Types III, IV and V construction. Prior to commencement of vertical construction of Type III, IV or V buildings that utilize any combustible building materials, the fire flow required by Sections 3313.3.1 through 3313.3.3 shall be provided, accompanied by fire hydrants in sufficient quantity to deliver the required fire flow and proper coverage.
[F] 3313.3.1 Fire separation up to 30 feet. Where a building of Type III, IV or V construction has a fire separation distance of less than 30 feet (9144 mm) from property lot lines, and an adjacent property has an existing structure or otherwise can be built on, the
2025 CALIFORNIA BUILDING CODE 33-7
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
SAFEGUARDS DURING CONSTRUCTION
water supply shall provide either a minimum of 500 gallons per minute (1893 L/m), or the entire fire flow required for the building when constructed, whichever is greater.
[F] 3313.3.2 Fire separation of 30 feet up to 60 feet. Where a building of Type III, IV or V construction has a fire separation distance of 30 feet (9144 mm) up to 60 feet (18 288 mm) from property lot lines, and an adjacent property has an existing structure or otherwise can be built on, the water supply shall provide a minimum of 500 gallons per minute (1893 L/m), or 50 percent of the fire flow required for the building when constructed, whichever is greater.
[F] 3313.3.3 Fire separation of 60 feet or greater. Where a building of Type III, IV or V construction has a fire separation of 60 feet (18 288 mm) or greater from a property lot line, a water supply of 500 gallons per minute (1893 L/m) shall be provided.
[F] 3313.4 Vertical construction, Types I and II construction. If combustible building materials are delivered to the construction site, water supply in accordance with Section 3313.2 shall be provided. Additional water supply for fire flow is not required prior to commencing vertical construction of Type I and II buildings.
[F] 3313.5 Standpipe supply. Regardless of the presence of combustible building materials, the construction type or the fire separation distance, where a standpipe is required in accordance with Section 3311, a water supply providing a minimum flow of 500 gallons per minute (1893 L/m) shall be provided. The fire hydrant used for this water supply shall be located within 100 feet (30 480 mm) of the fire department connection supplying the standpipe.
SECTION 3314—FIRE WATCH DURING CONSTRUCTION
CWUIC § 3311.3 High relevance — show source text
[F] 3311.3 Detailed requirements. Standpipes shall be installed in accordance with the provisions of Chapter 9.
Exception: Standpipes shall be either temporary or permanent in nature, and with or without a water supply, provided that such standpipes conform to the requirements of Section 905 as to capacity, outlets and materials.
SECTION 3312—AUTOMATIC SPRINKLER SYSTEM
[F] 3312.1 Completion before occupancy. In buildings where an automatic sprinkler system is required by this code, it shall be unlawful to occupy any portion of a building or structure until the automatic sprinkler system installation has been tested and approved, except as provided in Section 111.3.
[F] 3312.2 Operation of valves. Operation of sprinkler control valves shall be permitted only by properly authorized personnel and shall be accompanied by notification of duly designated parties. When the sprinkler protection is being regularly turned off and on to facilitate connection of newly completed segments, the sprinkler control valves shall be checked at the end of each work period to ascertain that protection is in service.
SECTION 3313—WATER SUPPLY FOR FIRE PROTECTION
[F] 3313.1 Where required. An approved water supply for fire protection, either temporary or permanent, shall be made available as soon as combustible building materials arrive on the site, on commencement of vertical combustible construction, and on installation of a standpipe system in buildings under construction, in accordance with Sections 3313.2 through 3313.5.
Exception: The fire code official is authorized to reduce the fire-flow requirements for isolated buildings or a group of buildings in rural areas or small communities where the development of full fire-flow requirements is impractical.
[F] 3313.2 Combustible building materials. When combustible building materials of the building under construction are delivered to a site, a minimum fire flow of 500 gallons per minute (1893 L/m) shall be provided. The fire hydrant used to provide this fire flow supply shall be within 500 feet (152 m) of the combustible building materials, as measured along an approved fire apparatus access lane. Where the site configuration is such that one fire hydrant cannot be located within 500 feet (152 m) of all combustible building materials, additional fire hydrants shall be required to provide coverage in accordance with this section.
[F] 3313.3 Vertical construction of Types III, IV and V construction. Prior to commencement of vertical construction of Type III, IV or V buildings that utilize any combustible building materials, the fire flow required by Sections 3313.3.1 through 3313.3.3 shall be provided, accompanied by fire hydrants in sufficient quantity to deliver the required fire flow and proper coverage.
[F] 3313.3.1 Fire separation up to 30 feet. Where a building of Type III, IV or V construction has a fire separation distance of less than 30 feet (9144 mm) from property lot lines, and an adjacent property has an existing structure or otherwise can be built on, the
2025 CALIFORNIA BUILDING CODE 33-7
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
SAFEGUARDS DURING CONSTRUCTION
water supply shall provide either a minimum of 500 gallons per minute (1893 L/m), or the entire fire flow required for the building when constructed, whichever is greater.
CWUIC § 1512.1 High relevance — show source text
SECTION 1512—WATER SUPPLY FOR FIRE PROTECTION
[F] 1512.1 When required. An approved water supply for fire protection, either temporary or permanent, shall be made available as soon as combustible building material arrives on the site, on commencement of vertical combustible construction, and on installation of a standpipe system in buildings under construction, in accordance with Sections 1512.1 through 1512.5.
Exception: The fire code official is authorized to reduce the fire-flow requirements for isolated buildings or a group of buildings in rural areas or small communities where the development of full fire-flow requirements is impractical.
[F] 1512.2 Combustible building materials. When combustible building materials of the building under construction are delivered to a site, a minimum fire flow of 500 gallons per minute (1893 L/m) shall be provided. The fire hydrant used to provide this fire flow supply shall be within 500 feet (152 m) of the combustible building materials as measured along an approved fire apparatus access lane. Where the site configuration is such that one fire hydrant cannot be located within 500 feet (152 m) of all combustible building materials, additional fire hydrants shall be required to provide coverage in accordance with this section.
[F] 1512.3 Vertical construction of Types III, IV and V construction. Prior to commencement of vertical construction of Type III, IV or V buildings that utilize any combustible building materials, the fire flow required by Sections 1512.3.1 through 1512.3.3 shall be provided, accompanied by fire hydrants in sufficient quantity to deliver the required fire flow and proper coverage.
[F] 1512.3.1 Fire separation up to 30 feet. Where a building of Type III, IV or V construction has a fire separation distance of less than 30 feet (9144 mm) from property lot lines, and an adjacent property has an existing structure or otherwise can be built on, the water supply shall provide either a minimum of 500 gallons per minute (1893 L/m), or the entire fire flow required for the building when constructed, whichever is greater.
[F] 1512.3.2 Fire separation of 30 feet up to 60 feet. Where a building of Type III, IV or V construction has a fire separation distance of 30 feet (9144 mm) up to 60 feet (18 288 mm) from property lot lines, and an adjacent property has an existing structure or otherwise can be constructed upon, the water supply shall provide a minimum of 500 gallons per minute (1893 L/m), or 50 percent of the fire flow required for the building when constructed, whichever is greater.
[F] 1512.3.3 Fire separation of 60 feet or greater. Where a building of Type III, IV or V construction has a fire separation of 60 feet (18 288 mm) or greater from a property lot line, a water supply of 500 gallons per minute (1893 L/m) shall be provided.
[F] 1512.4 Vertical construction, Types I and II construction. If combustible construction materials are delivered to the construction site, water supply in accordance with Section 1509.2 shall be provided. Additional water supply for fire flow is not required prior to commencing vertical construction of Type I and II buildings.
Frequently asked questions
Who decides the numeric gpm required for my new home in the WUI?
The CWUIC requires the water supply to meet the required fire‑flow, but the numeric gpm and duration are determined using the California Fire Code Appendix B (or BB) and by the fire‑code official or AHJ applying those tables and any applicable local amendments .
Can the fire‑flow requirement be reduced for a remote property?
Yes. The California Fire Code (Appendix B) authorizes the fire‑code official to reduce fire‑flow requirements for isolated buildings or small communities where full fire‑flow is impractical — you must coordinate with the AHJ for any reduction .
If there’s no municipal water, can I use a pond or tank?
Yes — CWUIC allows approved draft sites at natural water sources and other approved on‑site supplies, but the draft site design, access and pumper access must comply with CWUIC requirements and be approved by the code official (see § 404.3) .
Does CWUIC list a universal gpm per house size?
No. CWUIC mandates an approved water supply and defers the numeric fire‑flow calculation to the California Fire Code Appendix B/BB (CWUIC § 404.5) — you must consult Appendix B for table values or ask the AHJ to apply the table to your project .
What if my design meets the required gpm but the hydrant spacing is far?
Hydrant number and spacing are addressed by referenced standards (Appendix C/CC of the California Fire Code) and by the AHJ; meeting the flow rate alone is not sufficient if hydrant location or accessibility prevents apparatus from using that flow — coordinate both supply and hydrant placement per CWUIC and Fire Code guidance (§ 404.4) .
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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