CWUIC · California Wildland-Urban Interface Code

What buildings/occupancies or conditions are excluded or treated differently?

Q: Which section tells me which rule to apply when two parts of the CWUIC conflict?

Apply the specific requirement over a general one, and when different sections call for different methods/materials apply the most restrictive option — see § 102.1 .

Q: Are small accessory structures always exempt?

No. Some accessory structures (for example Group U accessory and Group U agricultural buildings) are excepted only when they meet explicit criteria (such as being located at least 50 feet from an applicable building) — see § 101.3.1 .

In plain terms: § 102.1 says use the specific rule if code sections disagree and always follow the most restrictive requirement; § 102.2 says CWUIC doesn’t cancel any local, state or federal law. Specific exclusions (like some accessory Group U buildings being exempt when at least 50 feet away) are listed elsewhere in Chapter 1 (see § 101.3.1), so check those sections plus local ordinances when determining whether a building is excluded or treated differently.

Ask a question free See coverage

Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

The California Wildland‑Urban Interface Code (CWUIC) says that when different parts of the code conflict, the specific requirement controls and the most restrictive requirement applies; and the CWUIC does not override other local, state or federal laws — these are the controlling rules in § 102.1 and § 102.2. § 102.1 and § 102.2 therefore determine how exclusions, exceptions, and alternate treatments are resolved when they appear elsewhere in the CWUIC or in other adopted law.

The single most important rule: when in doubt, apply the specific rule over a general one, and always apply the most restrictive requirement between overlapping rules (CWUIC § 102.1), while remembering the CWUIC cannot nullify other applicable laws (CWUIC § 102.2).

Requirements in detail

Core applicability rules (what § 102 says)

§ 102.1 — Conflict resolution. Where a general requirement and a specific requirement conflict, the specific requirement governs; where different sections specify different materials or methods, the most restrictive requirement controls.
§ 102.2 — Other laws. The CWUIC “shall not be deemed to nullify any provisions of local, state or federal law.” That means more restrictive local ordinances or other state/federal requirements remain in force.

Note: § 102 gives the rules for resolving conflicts and for interaction with other laws; the actual lists of occupancies or conditions that are excluded or treated differently are found elsewhere in the CWUIC (see next subsection).

Where the code says some buildings get different treatment or are excepted

The CWUIC contains explicit exceptions and limited-scope applications elsewhere in Chapter 1 (examples below). Those exceptions are applied under the conflict/priority rules in § 102.1. Examples include:

Accessory Group U buildings a minimum distance from an applicable building may be excepted.
Agricultural Group U buildings are treated differently when they meet distance criteria.
Additions/remodels to buildings constructed prior to July 1, 2008 may be excepted from full new‑building requirements.
These examples (and the numeric thresholds) appear in the CWUIC chapter on application and exceptions (see § 101.3.1 and its listed exceptions).

Decision table — dimensions you check to decide whether a building/condition is excluded or treated differently

Decision dimension	Typical values / threshold	What to check	Code reference
Type of requirement in conflict	General vs Specific	Apply the specific requirement	§ 102.1
If two requirements differ	Less restrictive vs More restrictive	Apply the most restrictive requirement	§ 102.1
Interaction with local/state/federal law	Any other applicable laws	CWUIC does not nullify other laws; apply all that are applicable (most restrictive prevails)	§ 102.2
Specific exceptions based on occupancy/distance	e.g., Group U accessory buildings located ≥ 50 feet from an applicable building	If thresholds met, the building may be excluded per exceptions in Chapter 1	§ 101.3.1 (exceptions list)
Date-based retrofit/applicability	Application date (e.g., permits submitted before/after specified dates; July 1, 2008)	Older buildings or permit dates may change which provisions apply	§ 101.3.1 and related application date language

Exceptions & special cases

Distance-based accessory exclusions: Small Group U accessory buildings are explicitly listed as exceptions when located at least 50 feet from an “applicable building” on the same lot; similarly, Group U agricultural buildings have a like distance exception — see the exception list in § 101.3.1. Apply these exceptions only after confirming the exact occupancy classification and measured distance.
Temporal (permit‑date) exceptions: The CWUIC’s application depends on the building permit submission date (see CWUIC application provisions). Some older permit dates trigger limited compliance requirements (e.g., limited sections only) — check the application-date language in § 101.3.1.
Where CWUIC text grants an exception or limited scope for a specific provision, that local allowance still must be reconciled with any more restrictive local, state or federal law under § 102.2.

If an occupancy or condition is not explicitly addressed in Chapter 1 or another CWUIC section, use the prioritization rules in § 102.1 to determine which provision applies, and then check for any overriding local/state/federal requirements per § 102.2.

Common mistakes

Assuming § 102 lists which occupancies are excluded — it does not. § 102.1 only tells you how to resolve conflicts; the actual exceptions/thresholds are located in other sections (for example § 101.3.1). Check both.
Ignoring local ordinances: many California cities/counties adopt more restrictive WUI rules — the CWUIC explicitly does not nullify those under § 102.2. Always confirm local law.
Forgetting time-based applicability: whether a building must comply can depend on the permit application date (see the application exceptions in § 101.3.1).

Worked example — concrete scenario

Scenario: A homeowner proposes a new detached Group U accessory building 40 feet from the main house on the same lot. The jurisdiction has adopted the CWUIC.

Step 1 — Check the accessory exception threshold: the CWUIC exception for Group U accessory buildings excludes them only when located at least 50 feet from an applicable building on the same lot (see § 101.3.1). Because the proposed building is 40 feet, it does not meet that exception and is therefore subject to CWUIC provisions applicable to accessory structures.

Step 2 — Resolve any conflicts: if a general CWUIC requirement and a specific accessory‑building provision differ, apply the specific rule; if the local ordinance has a stricter requirement (for example a 60‑foot exclusion or different material standard), apply the most restrictive result under § 102.1 and remember § 102.2 requires compliance with other laws.

Net: the 40‑ft accessory building is regulated by CWUIC rules for accessory buildings, and you must also check whether any local ordinance imposes a stricter rule.

Related provisions

§ 102.1 — General conflict/most‑restrictive rule (primary conflict‑resolution rule).
§ 102.2 — CWUIC does not nullify other laws (local/state/federal interaction).
§ 101.2 — Scope of the CWUIC (what the code applies to).
§ 101.3.1 — Application and explicit exceptions (distance thresholds, occupancy exceptions, permit‑date rules).
§ 101.4 — Retroactivity statements (what existing conditions the code applies to).

Code references

Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:

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 § 4.1 High 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

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

2025 CWUIC—continued	Col2	Adopted Yes/No	IWUIC Section	CBC Section	CFC Section	Title 14, Division 1.5 Section	Title 19, Division 1 Section	Gov Code Section	PRC Section	HSC Section
Section	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 § 503.1 High relevance — show source text

1||||||| |502|RESERVED|N||||||||| |503|Ignition-resistant
construction and
material|Y||704A||||||| |503.1|General|Y||701A.3||||||| |503.2|Ignition-resistant
building material|Y||707A.3 #2||||||| |503.2.1|Noncombustible
material|Y||704A.4 #1||||||| |503.2.2|Fire-retardant-
treated wood|Y||704A.4 #2||||||| |503.2.3|Fire-retardant-
treated wood roof
coverings|Y||705A.1||||||| |503.2.4|Other ignition-
resistant building
material|Y||704A.3||||||| |503.2.4.1|Flame spread|Y||704A.3 #1||||||| |503.2.4.2|Flame front|Y||704A.3 #2||||||| |503.2.4.3|Weathering|Y||703A.5.1||||||| |503.2.4.3.1|Evaluation require-
ments for weathering|Y||703A.5.2
703A.5.2.1||||||| |503.2.4.3.2|Wood-plastic
composite materials|Y||703A.6|||||||

APPENDIX H-28 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

2025 CWUIC—continued	Col2	Adopted Yes/No	IWUIC Section	CBC Section	CFC Section	Title 14, Division 1.5 Section	Title 19, Division 1 Section	Gov Code Section	PRC Section	HSC Section
Section	Title	Title	Title	Title	Title	Title	Title	Title	Title	Title
Chapter 5	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations	Special building construction regulations
503.2.4.3.3	Plastic lumber materials	Y		703A.6
503.2.5	Surface treatment protection	Y		703A.5.3
503.3	Standards of quality	Y		703A.1
503.3.1	Qualification by testing	Y		703A.2
503.3.2	Approved agency	Y		703A.3
503.3.3	Labeling	Y		703A.4
_503.3.

CWUIC § 2.1 High relevance — show source text

In Group R-2.1, Condition 2, the assembly point for residents is permitted to be within an adjacent smoke compartment.
In Group R-4, actual exiting from emergency escape and rescue openings shall not be required. Opening the emergency escape and rescue openings and signaling for help shall be an acceptable alternative.
In Group I-3, Conditions 2 through 5 where a defend-in-place response is permitted, the assembly point for detainees is permitted to be within an adjacent smoke compartment.
In Group I-3, Conditions 2 through 5, movement of detainees is not required to an assembly point where there are security concerns.

405.3 Frequency. Required emergency evacuation drills shall be held at the intervals specified in Table 405.3 or more frequently where necessary to familiarize all occupants with the drill procedure.

[California Code of Regulations, Title 19, Division 1, §3.13(a)(1)] Fire Drills. (Group E Occupancies)

(a) Group E Occupancies.

(1) General. Every person and public officer managing, controlling or in charge of any public, private or parochial school shall cause the fire alarm signal to be sounded upon the discovery of fire. Every person and public officer managing, controlling or in charge of any public, private or parochial school, other than a two-year community college, shall cause the fire alarm signal to be sounded not less than once every calendar month at the elementary and intermediate levels, and not less than twice yearly at the secondary level, in the manner prescribed in California Code of Regulations, Title 24, Part 2, Section 907.

A fire drill shall be held at the secondary level not less than twice every school year.

TABLE 405.3—FIRE AND EVACUATION DRILL FREQUENCY AND PARTICIPATION	Col2	Col3
GROUP OR OCCUPANCY	FREQUENCY	PARTICIPATION
Group A	Quarterly	Staff
Group Ba	Annually	All occupants
Group B (Ambulatory care facilities)	Quarterly on each shift	Staff
Group Ba (Clinic, outpatient)	Annually	Staff
Group E	See Section 403.4	All occupants
Group F	Annually	Employees
Group I-1c	Semiannually on each shift	All occupants
Group I-2	Quarterly on each shift	Staff
Group I-3	Quarterly on each shift	Staff
Group I-4	Monthly on each shift	All occupants
Group R-1	Quarterly on each shift	Employees
Group R-2b	See Section 403.9.2	All occupants
Group R-4c	Semiannually on each shift	All occupants
a. Emergency evacuation drills are required in Group B buildings having an occupant load of 500 or more persons or more than 100 persons above or below the lowest level of exit discharge. b. Emergency evacuation drills in Group R-2 college and university buildings shall be in accordance with Section 403.9.2.1. Other Group R-2 occupancies shall be in accordance with Section 403.9.2.2. c. In Groups I-1 and R-4, see Sections 403.7.1.4 and 403.9.3.4 for additional drills for staff.	a.

CWUIC § 2506.2 High relevance — show source text
[BS] GYPSUM PANEL PRODUCT. The general name for a family of sheet products consisting essentially of gypsum complying with the standards specified in Table 2506.2, Table 2507.2 and Chapter 35.

[BS] GYPSUM PLASTER. A mixture of calcined gypsum or calcined gypsum and lime and aggregate and other approved materials as specified in this code.

[BS] GYPSUM SHEATHING. Gypsum panel products specifically manufactured with enhanced water resistance for use as a substrate for exterior surface materials.

[BS] GYPSUM VENEER PLASTER. Gypsum plaster applied to an approved base in one or more coats normally not exceeding [1] / 4 inch (6.4 mm) in total thickness.

[BS] GYPSUM WALLBOARD. A gypsum board used primarily as an interior surfacing for building structures.

[BG] HABITABLE SPACE. A space in a building for living, sleeping, eating or cooking. Bathrooms, toilet rooms, closets, halls, storage or utility spaces and similar areas are not considered habitable spaces.

HALL CALL CONSOLE. [DSA-AC] An elevator call user interface exclusive to a destination-oriented elevator system that requires the user to select a destination floor prior to entering the elevator car.

[F] HALOGENATED EXTINGUISHING SYSTEM. A fire-extinguishing system using one or more atoms of an element from the halogen chemical series: fluorine, chlorine, bromine and iodine.

[F] HANDLING. The deliberate transport by any means to a point of storage or use .

2025 CALIFORNIA BUILDING CODE 2-35

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

DEFINITIONS

[BE] HANDRAIL. A horizontal or sloping rail intended for grasping by the hand for guidance or support.

HANDWASHING FIXTURE. Refer to the California Plumbing Code, Section 210.0.

HANDWASHING FIXTURE. [OSHPD 1, 2, 3, 4 & 5] A lavatory provided in patient rooms, nurse stations and other patient care areas intended for staff hygiene and infection control. These special-use lavatories are an element of a handwashing station as defined in Section 1224.3. Refer to the California Plumbing Code Section 210.0 definition for additional requirements associated with handwashing fixtures.

[BS] HARDBOARD. A fibrous-felted, homogeneous panel made from lignocellulosic fibers consolidated under heat and pressure in a hot press to a density not less than 31 pcf (497 kg/m [3] ).

HARDWARE. See “Fire exit hardware” and “Panic hardware.”

[F] HAZARDOUS MATERIALS. Those chemicals or substances that are physical hazards or health hazards as classified in Section 307 and the California Fire Code, whether the materials are in usable or waste condition.

[F] HAZARDOUS PRODUCTION MATERIAL (HPM). A solid, liquid or gas associated with semiconductor manufacturing that has a degree-of-hazard rating in health, flammability or instability of Class 3 or 4 as ranked by the California Electrical Code and which is used directly in research, laboratory or production processes which have as their end product materials that are not hazardous.
CWUIC § 17958.5 Medium relevance — show source text
Amendments, additions and deletions to this code adopted by a city, county, or city and county_ pursuant to California Health and Safety Code Sections 17958.5, 17958.7 and 18941.5, together with all applicable portions of this code, shall also become effective 180 days after publication of the California Building Standards Code by the California Building Standards Commission.

1.8.6.2 Findings, filings and rejections of local modifications. Prior to making any modifications or establishing more restrictive building standards, the governing body shall make express findings and filings, as required by California Health and Safety Code Section 17958.7, showing that such modifications are reasonably necessary due to local climatic, geological or topographical conditions. No modification shall become effective or operative unless the following requirements are met: 1. The express findings shall be made available as a public record. 2. A copy of the modification and express finding, each document marked to cross-reference the other, shall be filed with the California Building Standards Commission for a city, county, or city and county and with the Department of Housing and Community Development for fire protection districts. 3. The California Building Standards Commission has not rejected the modification or change.

Nothing in this section shall limit the authority of fire protection districts pursuant to California Health and Safety Code Section 13869.7(a).

SECTION 1.8.7—ALTERNATE MATERIALS, DESIGNS, TESTS AND METHODS OF CONSTRUCTION

1.8.7.1 General. The provisions of this code, as adopted by the Department of Housing and Community Development are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, design or method of construction not specifically prescribed by this code. Consideration and approval of alternates shall comply with Section 1.8.7.2 for local building departments and Section 1.8.7.3 for the Department of Housing and Community Development.

1.8.7.2 Local building departments. The building department of any city, county, or city and county may approve alternates for use in the erection, construction, reconstruction, movement, enlargement, conversion, alteration, repair, removal, demolition or arrangement of apartments, condominiums, hotels, motels, lodging houses, dwellings or accessory structures, except for the following: 1. Structures located in mobilehome parks as defined in California Health and Safety Code Section 18214. 2. Structures located in special occupancy parks as defined in California Health and Safety Code Section 18862.43. 3. Factory-built housing as defined in California Health and Safety Code Section 19971.

1.8.7.2.1 Approval of alternates. The consideration and approval of alternates by a local building department shall comply with the following procedures and limitations: 1. The approval shall be granted on a case-by-case basis. 2. Evidence shall be submitted to substantiate claims that the proposed alternate, in performance, safety and protection of life and health, conforms to, or is at least equivalent to, the standards contained in this code and other rules and regulations promulgated by the Department of Housing and Community Development. 3. The local building department may require tests performed by an approved testing agency at the expense of the owner or owner’s agent as proof of compliance. _4.

CWUIC § 1.7 Medium relevance — show source text

1.7_|Turnouts|Y||||1273.06||||| |403.1.8|Road and driveway
structures|Y||||1273.07(a)
1273.07(b)
1273.07(c)
1273.07(d)||||| |403.1.9|Dead-end roads|Y||||1273.08(a)
1273.08(b)||||| |403.10|Gate Entrances|Y||||1273.09(a)
1273.09(b)
1273.09(c)
1273.09(d)||||| |403.2|Signing and Building
Numbering|Y||||Article 3||||| |403.2.1|Intent|Y||||1274.00||||| |403.2.2|Road signs|Y||||1274.01||||| |403.2.3|Road Sign
Installation, Location
and Visibility|Y||||1274.02(a)
1274.02(b)
1274.02(c)
1274.02(d)||||| |403.2.4|Addresses for
Buildings|Y||||1274.03(a)
1274.03(b)
1274.03(c)||||| ||||||||||||

2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX H-27

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

2025 CWUIC—continued	Col2	Adopted Yes/No	IWUIC Section	CBC Section	CFC Section	Title 14, Division 1.5 Section	Title 19, Division 1 Section	Gov Code Section	PRC Section	HSC Section
Section	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
403.2.5	Address installation, location, and visibility	Y				1274.04(a) 1274.04(b) 1274.04(c) 1274.04(d) 1274.04(e) 1274.04(f)
404	Water supply	Y				1275.02
404.1	General	Y			507	1275.02(b)
404.2	Required water supply	Y				1275.02(c)
404.3	Draft sites	Y
404.3.1	Access	Y			507.5.4
404.3.

CWUIC § 1.1.7 Medium relevance — show source text
1.1.7 Order of precedence and use.

1.1.7.1 Differences. In the event of any differences between these building standards and the standard reference documents, the text of these building standards shall govern.

1.1.7.2 Specific provisions. Where a specific provision varies from a general provision, the specific provision shall apply.

1.1.7.3 Conflicts. When the requirements of this code conflict with the requirements of any other part of the California Building Standards Code, Title 24 the most restrictive requirements shall prevail.

1.1.7.3.1 Detached one- and two-family dwellings. Detached one- and two-family dwellings, lodging houses, live/work units, townhouses not more than three stories above grade plane in height with a separate means of egress, and their accessory structures, may be designed and constructed in accordance with the California Residential Code or the California Building Code, but not both, unless the proposed structure(s) or element(s) exceed the design limitations established in the California Residential Code, and the code user is specifically directed by the California Residential Code to use the California Building Code.

1-4 2025 CALIFORNIA EXISTING BUILDING CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

ADMINISTRATION

1.1.8 City, county, or city and county amendments, additions or deletions. The provisions of this code do not limit the authority of city, county, or city and county governments to establish more restrictive and reasonably necessary differences to the provisions contained in this code pursuant to complying with Section 1.1.8.1. The effective date of amendments, additions or deletions to this code by a city, county, or city and county filed pursuant to Section 1.1.8.1 shall be the date filed. However, in no case shall the amendments, additions or deletions to this code be effective any sooner than the effective date of this code.

Local modifications shall comply with Health and Safety Code Section 18941.5 for Building Standards Law, Health and Safety Code Section 17958 for State Housing Law or Health and Safety Code Section 13869.7 for Fire Protection Districts.

1.1.8.1 Findings and filings. 1. The city, county, or city and county shall make express findings for each amendment, addition or deletion based upon climatic, topographical or geological conditions.

Exception: Hazardous building ordinances and programs mitigating unreinforced masonry buildings. 2. The city, county, or city and county shall file the amendments, additions or deletions expressly marked and identified as to the applicable findings. Cities, counties, cities and counties, and fire departments shall file the amendments, additions or deletions, and the findings with the California Building Standards Commission at 2525 Natomas Park Drive, Suite 130, Sacramento, CA 95833.

3. Findings prepared by fire protection districts shall be ratified by the local city, county, or city and county and filed with the California Department of Housing and Community Development, Division of Codes and Standards, P.O. Box 278180, Sacramento, CA 95827-8180 or 9342 Tech Center Drive, Suite 500, Sacramento, CA 95826-2581.
CWUIC § 1.11 Medium relevance — show source text
shall not become operative within any city or county unless and until the governing body of the city or county makes an_ express finding that the application of those regulations within the city or county is reasonably necessary because of local conditions and the city or county files a copy of that finding with the department. (b) In adopting ordinances or regulations for limited-density owner-built rural dwellings, a city or county may make such changes or modifications in the requirements contained in Article 8 (commencing with Section 74) of Subchapter 1 of Chapter 1 of Title 25 of the California Code of Regulations that it determines are reasonably necessary because of local conditions, if the city or county files a copy of the changes or modifications and the express findings for the changes or modifications with the department. No change or modification of that type shall become effective or operative for any purpose until the finding and the change or modification has been filed with the department.

LISTED. (HCD 1) All products that appear in a list published by an approved testing or listing agency. For additional information, see Health and Safety Code Section 17920(h).

[RB] LISTED. (SFM) Equipment, materials, products or services included in a list published by an organization acceptable to the code official and concerned with evaluation of products or services that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services and whose listing states either that the equipment, material, product or service meets identified standards or has been tested and found suitable for a specified purpose. Terms that are used to identify listed equipment, products or materials include “listed,” “certified,” “classified” or other terms as determined appropriate by the listing organization. For applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, “listed” shall also mean equipment or materials accepted by the state fire marshal as conforming to the provisions of the State Fire Marshal’s regulations and which are included in a list published by the State Fire Marshal.

LISTING AGENCY. (HCD 1 & HCD 2) An agency approved by the department that is in the business of listing and labeling products, mate- rials, equipment and installations tested by an approved testing agency, and that maintains a periodic inspection program on current production of listed products, equipment and installations, and that, at least annually, makes available a published report of these list- ings. For additional information, see Health and Safety Code Section 17920(i).

[RB] LIVE LOADS. Those loads produced by the use and occupancy of the building or other structure and do not include construction or environmental loads such as wind load, snow load, rain load, earthquake load, flood load or dead load.

[RB] LIVE/WORK UNIT. A dwelling unit or sleeping unit in which a significant portion of the space includes a nonresidential use that is operated by the tenant or building owner.

[MP] LIVING SPACE. Space within a dwelling unit utilized for living, sleeping, eating, cooking, bathing, washing and sanitation purposes.

[MP] LOCAL EXHAUST. An exhaust system that uses one or more fans to exhaust air from a specific room or rooms within a dwelling.

[MP] LOCKING-TYPE TAMPER-RESISTANT CAP. A cap designed to be unlocked by a specially designed tool or key to prevent removal of the cap by means of hand-loosening or by commonly available tools.

2-16 2025 CALIFORNIA RESIDENTIAL CODE
California Building Code Medium relevance — show source text
STANDPIPE, TYPES OF. Standpipe types are as follows:

Automatic dry. A dry standpipe system, normally filled with pressurized air, that is arranged through the use of a device, such as a dry pipe valve, to admit water into the system piping automatically upon the opening of a hose valve. The water supply for an automatic dry standpipe system shall be capable of supplying the system demand.

Automatic wet. A wet standpipe system that has a water supply that is capable of supplying the system demand automatically.

Manual dry. A dry standpipe system that does not have a permanent water supply attached to the system. Manual dry standpipe systems require water from a fire department pumper to be pumped into the system through the fire department connection in order to supply the system demand.

Manual wet. A wet standpipe system connected to a water supply for the purpose of maintaining water within the system but which does not have a water supply capable of delivering the system demand attached to the system. Manual wet standpipe systems require water from a fire department pumper (or the like) to be pumped into the system in order to supply the system demand.

Semiautomatic dry. A dry standpipe system that is arranged through the use of a device, such as a deluge valve, to admit water into the system piping upon activation of a remote control device located at a hose connection. A remote control activation device shall be provided at each hose connection. The water supply for a semiautomatic dry standpipe system shall be capable of supplying the system demand.

STANDPIPE SYSTEM, CLASSES OF. Standpipe system classes are as follows: Class I system. A system providing 2 [1] / 2 -inch (64 mm) hose connections to supply water for use by fire departments and those trained in handling heavy fire streams. Class II system. A system providing 1 [1] / 2 -inch (38 mm) hose stations to supply water for use primarily by the building occupants or by the fire department during initial response. Class III system. A system providing 1 [1] / 2 -inch (38 mm) hose stations to supply water for use by building occupants and 2 [1] / 2 -inch (64 mm) hose connections to supply a larger volume of water for use by fire departments and those trained in handling heavy fire

streams.

STATE-OWNED/LEASED BUILDING. A building or portion of a building that is owned, leased or rented by the state. State-leased buildings shall include all required exits to a public way serving such leased area or space. Portions of state- leased buildings that are not leased or rented by the state shall not be included within the scope of this section unless such portions present an exposure hazard to the state- leased area or space.

STATIC PILES. Piles in which processed wood product or solid biomass feedstock is mounded and is not being turned or moved.

STEEL. Hot- or cold-rolled as defined by the California Building Code .

STORAGE, HAZARDOUS MATERIALS. The keeping, retention or leaving of hazardous materials in closed containers, tanks, cylinders, or similar vessels; or vessels supplying operations through closed connections to the vessel.

CWUIC § 1.5 Medium relevance — show source text

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS

2025 CWUIC—continued	Col2	Adopted Yes/No	IWUIC Section	CBC Section	CFC Section	Title 14, Division 1.5 Section	Title 19, Division 1 Section	Gov Code Section	PRC Section	HSC Section
Section	Title	Title	Title	Title	Title	Title	Title	Title	Title	Title
Chapter 2	Definitions	Definitions	Definitions	Definitions	Definitions	Definitions	Definitions	Definitions	Definitions	Definitions
	Multilayered glazed panels	Y
	Noncombustible roof covering	Y
	Outbuilding (T14)	Y				1299.02(c)
	Peer review	Y
	Rafter tail	Y		702A
	Registered design professional	Y
	Residential unit (T14)	Y				1270.01(w)
	Ridgeline (topography) (T14)	Y				1270.01(x)
	Road (T14)	Y				1270.01(y)
	Roof assembly	Y
	Roof covering	Y
	Roof covering system	Y
	Roof deck	Y
	Roof eave	Y		702A
	Roof eave soffit	Y		702A
	Slope	Y
	State Responsibility Area (SRA)	Y		702A	4902.1
	Strategic ridgeline (T14)	Y				1270.01(dd)
	Structure	Y	202			1270.01(ee)
	Subdivision	Y
	Tree crown	Y
	Undeveloped ridgeline (T14)	Y				1270.01(ii)
	Unenclosed acces- sory structure	Y
	Vertical curve (T14)	Y				1270.01(k)
	Wildfire	Y		702A	4902.1
	Wildfire exposure	Y		702A	4902.1
	Wildland	Y
	Wildland-urban inter- face area	Y		702A	4902.1
Chapter 3	Wildland-urban interface areas	Wildland-urban interface areas	Wildland-urban interface areas	Wildland-urban interface areas	Wildland-urban interface areas	Wildland-urban interface areas	Wildland-urban interface areas	Wildland-urban interface areas	Wildland-urban interface areas	Wildland-urban interface areas
301	General	Y
301.1	Scope	Y								4201
301.

CWUIC § 1-15 Medium relevance — show source text
All unincorporated lands designated by the State Board of Forestry and Fire Protection as State Responsibility Area (SRA) including:

Moderate Fire Hazard Severity Zones.

High Fire Hazard Severity Zones.

Very High Fire Hazard Severity Zones.

Land designated as a Very High Fire Hazard Severity Zone by cities and other local agencies.

2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 1-15

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

ADMINISTRATION

Land designated as a wildland-urban interface area by cities and other local agencies.

Exceptions: 1. New buildings located in any Fire Hazard Severity Zone within a State Responsibility Area, for which an application for a building permit is submitted on or after January 1, 2008, shall comply with this code. 2. New buildings located in any Fire Hazard Severity Zone within a State Responsibility Area or any wildland-urban interface area designated by cities and other local agencies for which an application for a building permit is submit- ted on or after December 1, 2005, but prior to July 1, 2008, shall only comply with the following sections of this chapter: 2.1. Section 507 – Replacement or Repair of Roof Coverings.

2.2. Section 504.10 – Vents.

[A] 101.4 Retroactivity. The provisions of the code shall apply to conditions arising after the adoption thereof, conditions not legally in existence at the adoption of this code and conditions that, in the opinion of the code official, constitute a distinct hazard to life or property.

Exception: Provisions of this code that specifically apply to existing conditions are retroactive.

[A] 101.5 Additions or alterations. Additions or alterations shall be permitted to be made to any building or structure without requiring the existing building or structure to comply with all of the requirements of this code, provided that the addition or alteration conforms to that required for a new building or structure.

Exception: Provisions of this code that specifically apply to existing conditions are retroactive.

Additions or alterations shall not be made to an existing building or structure that will cause the existing building or structure to be in violation of any of the provisions of this code nor shall such additions or alterations cause the existing building or structure to become unsafe. An unsafe condition shall be deemed to have been created if an addition or alteration will cause the existing building or structure to become structurally unsafe or overloaded; will not provide adequate access in compliance with the provisions of this code or will obstruct existing exits or access; will create a fire hazard; will reduce required fire resistance or will otherwise create conditions dangerous to human life.

[A] 101.6 Maintenance. Buildings, structures, landscape materials, vegetation, defensible space or other devices or safeguards required by this code shall be maintained in conformance to the code edition under which installed. The owner or the owner’s authorized agent shall be responsible for the maintenance of buildings, structures, landscape materials and vegetation.

SECTION 102—APPLICABILITY

[A] 102.1 General. Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall govern. Where, in any specific case, different sections of this code specify different materials, methods of construction or other requirements, the most restrictive shall govern.

[A] 102.2 Other laws. The provisions of this code shall not be deemed to nullify any provisions of local, state or federal law.

Frequently asked questions

Which section tells me which rule to apply when two parts of the CWUIC conflict?

Apply the specific requirement over a general one, and when different sections call for different methods/materials apply the most restrictive option — see § 102.1.

Does the CWUIC override my city’s more restrictive wildfire ordinance?

No. The CWUIC “shall not be deemed to nullify any provisions of local, state or federal law.” If a local ordinance is more restrictive, it still applies — see § 102.2.

Are small accessory structures always exempt?

No. Some accessory structures (for example Group U accessory and Group U agricultural buildings) are excepted only when they meet explicit criteria (such as being located at least 50 feet from an applicable building) — see § 101.3.1.

If a building permit was filed before a CWUIC adoption date, does the CWUIC apply?

It depends on the permit submission date and the CWUIC’s application-date language and exceptions in § 101.3.1; certain older permits may have limited CWUIC requirements.

Where do I find the numeric thresholds and occupancy lists that determine exclusions?

Those specifics are found in Chapter 1 exceptions and in the sections that define applicability and exceptions (for example § 101.3.1), not in § 102 itself.

Ask about the CWUIC

Get cited, plain-English answers on the California Wildland-Urban Interface Code for your project — any code section, any scenario.

Start Free Trial

Related in the CWUIC

What is the scope, purpose and general requirements of the CWUIC?

Which state/local agencies and California adoptions apply to the CWUIC?

Scope and Applicability

California Wildland-Urban Interface Code

What buildings/occupancies or conditions are excluded or treated differently?

What the code requires — 2-4 sentences

Requirements in detail

Core applicability rules (what § 102 says)

Where the code says some buildings get different treatment or are excepted

Decision table — dimensions you check to decide whether a building/condition is excluded or treated differently

Exceptions & special cases

Common mistakes

Worked example — concrete scenario

Related provisions

Code references

Frequently asked questions

More in California Wildland-Urban Interface Code

Ask about the CWUIC

Related in the CWUIC