CWUIC · California Wildland-Urban Interface Code

What defensible space distances and standards apply (PRC 4291 / CWUIC)?

Keep a 100‑foot defensible space from your house where possible: an ember‑resistant zone within 5 feet, the most aggressive thinning between 5 and 30 feet, and continued fuel reduction out to 30–100 feet — but remember you cannot clear past your property line unless law or agreement allows it (PRC §4291; CWUIC §604.1).

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

Landowners must maintain defensible space around structures per § 4291 of the Public Resources Code and the CWUIC maintenance rules in § 604.1. The baseline requirement is 100 feet of fuel modification measured from the structure outward (but not beyond the property line unless otherwise authorized), with more intensive treatments close to the building — an ember‑resistant zone within 5 feet, stronger reductions between 5 and 30 feet, and management out to 100 feet (subject to property line limits and local/state law). These requirements and the definitions that apply are set out in § 4291 and CWUIC Chapter 6 maintenance sections (see § 604.1 and related provisions).

The single most important point: keep the area immediately around the building cleared and arranged so wildfire under average conditions is unlikely to ignite the structure — generally 100 ft of defensible space from the structure, with an ember‑resistant zone within 5 ft and the most intense fuel reduction 5–30 ft from the building.

Requirements in detail

Key defined terms (first use bolded)

Defensible space — the required buffer between a Building or Structure and surrounding vegetation that could ignite; defined and required by § 4291 and referenced in CWUIC Chapter 6.
Fuel — any combustible material (including landscape plants, grasses, weeds, petroleum‑based products); used in § 4291 fuel modification discussion.
Ember‑resistant zone — the immediate perimeter where materials likely to be ignited by embers should be eliminated or managed (required within 5 ft per guidance in § 4291).

Decision‑relevant distances and requirements (quick reference table)

Decision dimension	Required value / standard	Code Reference
Total defensible space from structure	100 feet (measured from each side and front/rear of the structure, but not beyond the property line unless law/ordinance allows)	PRC § 4291
Zone 1 (inner zone)	0–30 feet from structure — more intensive fuel reduction (clearances, spacing, ignition‑resistant plants/maintenance)	CWUIC § 1299.03 / CCR Title 14 guidance; referenced by CWUIC § 604.3
Ember‑resistant zone	Within 5 feet of the structure — remove materials likely to ignite from embers (highest intensity)	PRC § 4291 (ember‑resistant zone language referenced)
Mid zone management	5–30 feet — more intense fuel reductions than the outer zone	PRC § 4291 (intensity varies; 5–30 ft highlighted)
Outer zone	30–100 feet — continued spacing and fuel reduction, but can be less intense; may stop at property line	PRC § 4291; CWUIC § 1299.03 description of Zone 2 (30–100 ft)
Chimney/stovepipe clearance	Remove tree portions that extend within 10 feet of chimney/stovepipe outlet	PRC § 4291 and CFC guidance
Outbuildings	Minimum 10 feet clearance down to bare mineral soil; vegetation >10 ft and <20 ft from outbuildings must be fire‑smart	CWUIC § 604.4
Special facilities (water tanks, pumps)	Defensible space of not less than 30 feet clear of non‑fire‑resistive vegetation	CWUIC (A107.3 in Appendix A) / referenced by CWUIC cross‑refs
Exceptional extensions	Up to 300 feet radius may be authorized for certain critical facilities or by director in special cases	PRC § 4291.3 (director / fire official authorization)
Property‑line limitation	Fuel modification required shall not extend beyond the property line except as allowed by state/local law and only with adjacent owner consent (or under specified authority)	PRC § 4291

How intensity varies by distance

0–5 ft (ember‑resistant zone): eliminate or replace materials likely to be ignited by embers; remove combustible items, keep roof/gutters clear. Strictest management.
5–30 ft: aggressive thinning and spacing of trees/shrubs; maintain noncombustible or low‑fuel landscaping; prune trees and keep crowns separated.
30–100 ft: reduce continuity of fuels (fuel breaks, spacing) so wildfire under average weather conditions is unlikely to transmit to the structure; can be less intensive than inner zone.

Exceptions & special cases

Local ordinances, state law, or an insurance company (with fire‑expert findings) may require a greater distance than 100 feet, but fuel modification beyond the property line can only be required or done under state/local legal authority and typically needs adjacent‑owner consent or statutory authorization. See § 4291 (subparagraphs B and C).
Fire officials or the director may authorize vegetation management or firebreaks up to 300 feet from a protected facility (hospitals, schools, tanks) or, in some cases, for other structures if necessary to protect life and property — see § 4291.3.
The 100‑foot requirement is measured from the structure; if the property line is closer than 100 ft, defensible space is required up to the property line (not beyond) unless a specific law or agreement allows otherwise. Property‑line limit is in § 4291.
Single, well‑maintained specimen trees may be left inside required zones if they are pruned and maintained such that they do not rapidly transmit fire to or from the structure (explicit allowance in § 4291).

Common mistakes

Assuming 100 ft always extends beyond the parcel: PRC § 4291 limits fuel modification to the property line unless other authority exists. Many homeowners mistakenly clear adjacent land without consent.
Treating outbuildings the same as a primary structure: CWUIC § 604.4 sets a 10 ft minimum clearance standard for outbuildings (different, and stricter for immediate clearance).
Forgetting the ember‑resistant zone: homeowners often focus on spacing at 30–100 ft but neglect the 5‑ft ember‑resistant zone that addresses ember ignition sources; § 4291 highlights stronger measures within 5 ft.
Measuring incorrectly (from property line vs. structure): defensible space distances are measured from the structure outward, not from the property line inward.
Not pruning around chimneys and stovepipes: § 4291 requires removal of tree parts within 10 ft of chimney or stovepipe outlets — an item commonly missed.

Worked example

Scenario: A single‑family home sits on a 0.8‑acre lot in a State Responsibility Area (SRA). The nearest property line is 80 feet from the house on the west side; the other sides have at least 150 ft to the property lines.

Apply the rules:

The baseline goal is 100 ft of defensible space from the structure, but because the west property line is at 80 ft, fuel modification on that side is required only to the property line (80 ft) unless the local ordinance or adjacent owner agreement allows more. (PRC § 4291).
On the east, south, and north sides there is space for 100 ft — create the three concentric management areas: 0–5 ft ember‑resistant zone (remove combustible mulch, store no firewood, use noncombustible hardscape where possible), 5–30 ft (thin shrubs, prune, increase spacing, remove ladder fuels), and 30–100 ft (space groups of shrubs and trees, remove dead material). (PRC § 4291; CWUIC guidance on Zones).
Trim any tree branches so none extend within 10 ft of chimney or stovepipe outlets. (PRC § 4291).
If the homeowner’s insurer requests a greater distance based on a fire expert’s findings, the insurer may require it per the § 4291 provisions — but such requests must follow the statutory process.

Related provisions

CWUIC § 604.1 — Maintenance of defensible space; ties CWUIC to PRC § 4291.
CWUIC § 604.3 — Lists laws/regulations to be used for hazardous vegetation maintenance (including PRC § 4291).
CWUIC § 604.4 — Outbuildings clearance (minimum 10 ft).
CWUIC § 603.4.2 — Tree management rules inside the 30‑foot zone (pruning, crown separation).
CWUIC § 1299.03 — Implementation guidance for defensible space Zones (30 ft / 30–100 ft description referenced by CWUIC).
PRC § 4291 — Primary statutory source for defensible space distances, ember‑resistant zone, chimney clearance, property‑line limits, and authority for greater distances/300‑ft exceptions.
PRC § 4291.3 — Authority to authorize firebreaks up to 300 ft for critical facilities or by director in special cases.

Code references

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

CWUIC § 4291 High relevance — show source text
4291.

(a) A person who owns, leases, controls, operates, or maintains a building or structure in, upon, or adjoining a mountainous area, forest-covered lands, shrub-covered lands, grass-covered lands, or land that is covered with flammable material, shall at all times do all of the following: (1) (A) Maintain defensible space of 100 feet from each side and from the front and rear of the structure, but not beyond the property line, except as provided in subparagraph (B). The amount of fuel modification necessary shall consider the flammability of the structure as affected by building material, building standards, location, and type of vegetation. Fuels shall be maintained and spaced in a condition so that a wildfire burning under average weather conditions would be unlikely to ignite the structure. This subparagraph does not apply to single specimens of trees or other vege- tation that are well-pruned and maintained so as to effectively manage fuels and not form a means of rapidly transmitting fire from other nearby vegetation to a structure or from a structure to other nearby vegetation or to interrupt the advance of embers toward a structure. The intensity of fuels management may vary within the 100-foot perimeter of the structure, with more intense fuel reductions being utilized between 5 and 30 feet around the struc- ture, and an ember-resistant zone being required within 5 feet of the structure, based on regulations promulgated by the board, in consultation with the department, to consider the elimination of materials in the ember-resistant zone that would likely be ignited by embers. Consistent with fuels management objectives, steps should be taken to mini- mize erosion, soil disturbance, and the spread of flammable nonnative grasses and weeds. For purposes of this subparagraph, “fuel” means any combustible material, including petroleum-based products, cultivated landscape plants, grasses, and weeds, and wildland vegetation. (B) A greater distance than that required under subparagraph (A) may be required by state law, local ordinance, rule, or regulation. Fuel modification beyond the property line may only be required by state law, local ordinance, rule, or regulation in order to maintain 100 feet of defensible space from a structure. Fuel modification on adjacent property shall only be conducted following written consent by the adjacent landowner. Any local ordinance related to fuel modification shall be in compliance with all applicable state laws, regulations, and policies. Any local ordinance may include provisions to allocate costs for any fuel modification beyond the property line.

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(C) An insurance company that insures an occupied dwelling or occupied structure may require a greater distance than that required under subparagraph (A) if a fire expert, designated by the director, provides findings that the fuel modi- fication is necessary to significantly reduce the risk of transmission of flame or heat sufficient to ignite the structure, and there is no other feasible mitigation measure possible to reduce the risk of ignition or spread of wildfire to the structure. The greater distance may not be beyond the property line unless allowed by state law, local ordinance, rule, or regulation. (2) Remove that portion of a tree that extends within 10 feet of the outlet of a chimney or stovepipe. (3) _Maintain a tree, shrub,
CWUIC § 1.5 High relevance — show source text
(g) Any local governmental entity that is qualified to conduct defensible space assessments pursuant to this section in very high and high fire hazard severity zones, as identified by the State Fire Marshal pursuant to Section 51178 of the Government Code or Article 9 (commencing with Section 4201) of this chapter or by a local agency pursuant to Section 51179 of the Government Code and reports that information to the department, shall report that information using the common reporting platform established pursuant to subdivision (c). (h) (1) On December 31, 2023, and annually thereafter, the department shall report to the Legislature all defensible space data collected pursuant paragraph (2) of subdivision (c). The report may include information on the proportion of unique parcels that were inspected, the degree of compliance with requirements set forth in Section 4291, any enforcement actions that may have been taken for noncompliant parcels, and the proportion of parcels that were found to be in compliance across jurisdictions. At minimum, the report shall include data with sufficient detail to facilitate comparisons of community compliance with the requirements of Section 4291 between local governmental entities qualified to conduct defensible space assessments pursuant to this section and local governmental entities that are not. (2) A report submitted pursuant to this subdivision shall be submitted in compliance with Section 9795 of the Government Code.

(i) This section shall remain in effect only until January 1, 2026, and as of that date is repealed.

SECTION H104—CALIFORNIA CODE OF REGULATIONS, TITLE 14, DIVISION 1.5

H104.1 Subchapter 2 State Minimum Fire Safe Regulations.

1270.01 Definitions.

(aa) Same Practical Effect: As used in this subchapter, means an Exception or alternative with the capability of applying accepted wildland fire suppression strategies and tactics, and provisions for fire fighter safety, including: (1) access for emergency wildland fire equipment, (2) safe civilian evacuation, (3) signing that avoids delays in emergency equipment response, (4) available and accessible water to effectively attack Wildfire or defend a Structure from Wildfire, and (5) fuel modification sufficient for civilian and fire fighter safety.

1270.02 Purpose. (a) Subchapter 2 has been prepared and adopted for the purpose of establishing state minimum Wildfire protection standards in conjunction with Building, construction, and Development in the State Responsibility Area (SRA) and, after July 1, 2021, the Very High Fire Hazard Severity Zones, as defined in Government Code § 51177(i) (VHFHSZ). (b) The future design and construction of Structures, subdivisions and Developments in the SRA and, after July 1, 2021, the VHFHSZ shall provide for basic emergency access and perimeter Wildfire protection measures as specified in the following articles. (c) These standards shall provide for emergency access; signing and Building numbering; private water supply reserves for emer- gency fire use; vegetation modification, Fuel Breaks, Greenbelts, and measures to preserve Undeveloped Ridgelines. Subchapter 2 specifies the minimums for such measures.

1270.03 Scope. (a) Subchapter 2 shall apply to: (1) the perimeters and access to all residential, commercial, and industrial Building construction within the SRA approved _after January 1, 1991, and those approved after July 1,
CWUIC § 602.2 High relevance — show source text
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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602.3.2 Final fire protection plan. Final fire protection plan shall include items listed in Section 602.3.1 and the following: 1. A map identifying all proposed plants in the fuel modification zones with a legend that includes a symbol for each proposed plant species. The plan shall include specific information on each species proposed, including but not limited to: 1.1. The plant life-form;

1.2. The scientific and common name; and

1.3. The expected height and width for mature growth. 2. Identification of irrigated and nonirrigated zones. 3. Requirements for vegetation reduction around emergency access and evacuation routes. 4. Identification of points of access for equipment and personnel to maintain vegetation in common areas. 5. Legally binding statements regarding community responsibility for maintenance of fuel modification zones. 6. Legally binding statements to be included in covenants, conditions and restrictions regarding property owner responsibili- ties for vegetation maintenance.

SECTION 603— VEGETATION PLAN

603.1 General. Planting of vegetation for new landscaping shall be selected to reduce vegetation in proximity to a structure and to maintain vegetation as it matures.

603.2 Application. All new plantings of vegetation in State Responsibility Area (SRA) and Local Responsibility Areas (LRA) designated as a Fire Hazard Severity Zone shall comply with Sections 603.3 through 603.4.2.1.
CWUIC § 1276.04 High relevance — show source text
_ prescribed burning, manual treatment, mechanical treatment, prescribed herbivory, and targeted ground application of herbicides.

(g) Where a Local Jurisdiction requires Fuel Breaks, maintenance mechanisms shall be established to ensure the fire behavior objectives and thresholds are maintained over time. (h) The mechanisms required shall be binding upon the property for which the Fuel Break is established, shall ensure adequate maintenance levels, and may include written legal agreements; permanent fees, taxes, or assessments; assessments through a homeowners' association; or other funding mechanisms.

1276.04 Greenbelts, greenways, open spaces and parks. (a) Where a Greenbelt, Greenway, open space, park, landscaped or natural area, or portions thereof, is intended to serve as a Fuel Break, the space or relevant portion thereof shall conform with the requirements in § 1276.03 (Fuel Breaks).

1276.05 Disposal of flammable vegetation and fuels.

The disposal, including burning or removal to a site approved by the Local Jurisdiction, in consultation with the Fire Authority, of flam- mable vegetation and fuels caused by site construction, Road, and Driveway construction shall be in accordance with all applicable laws and regulations.

H104.2 Subchapter 3 Fire Hazard.

Article 3. Fire Hazard Reduction Around Buildings and Structures

1299.01 Purpose. The intent of this regulation is to provide guidance for implementation of Public Resources Code Section 4291 to improve safety for fire fighters defending a home as well as increase the survivability of a “Building or Structure” as defined, that exists in grass, brush, and forest covered lands within the designated State Responsibility Area (SRA) of California.

1299.02 Definitions. The following definitions apply to this article: (a) 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.

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(b) Building or Structure. Anything constructed that is designed or intended for support, enclosure, shelter, or protection of persons, animals, or property, having a permanent roof that is supported by walls or posts that connect to, or rest on the ground. (c) Outbuilding. Buildings or structures that are less than one hundred-twenty (120) square feet in size and not used for human habitation. For purposes of this Section, an “Outbuilding” is not a “Building or Structure” as defined in subsection (b) above.

1299.03 Requirements. Defensible space is required to be maintained at all times, whenever flammable vegetative conditions exist. One hundred feet (100 ft.) of defensible space clearance shall be maintained in two distinct “Zones” as follows: “Zone 1” extends thirty feet (30 ft.) out from each “Building or Structure,” or to the property line, whichever comes first; “Zone 2” extends from thirty feet (30 ft.) _to one hundred feet (100 ft.) from each “Building or Structure,” but not beyond the property line.
CWUIC § 1.5 High relevance — show source text
structure.

(c) (1) The director shall establish a common reporting platform that allows defensible space and home hardening assessment data, collected by the qualified entities, to be reported to the department and shall establish any necessary quality control measure to ensure that the assessment data is accurate and reliable.

(2) The department shall compile the data submitted pursuant to paragraph (1). (d) The director may use the defensible space and home hardening assessment data to do any of the following: (1) Direct inspection and enforcement resources away from landowners who meet or exceed the department’s standards and regulations for maintaining defensible space.

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(2) Direct inspection and enforcement resources toward landowners who do not meet the department’s standards and regulations for maintaining defensible space. (3) Direct educational resources toward landowners who own or maintain structures that can be hardened to make them more resistant to fire.

(4) Assist in estimating defensible space compliance in the state responsibility area. (e) The department may expand or amend existing programs for the implementation of this section. (f) This section does not grant any right of entry onto private land or regulatory or enforcement authority to participating quali- fied entities.

(g) Any local governmental entity that is qualified to conduct defensible space assessments pursuant to this section in very high and high fire hazard severity zones, as identified by the State Fire Marshal pursuant to Section 51178 of the Government Code or Article 9 (commencing with Section 4201) of this chapter or by a local agency pursuant to Section 51179 of the Government Code and reports that information to the department, shall report that information using the common reporting platform established pursuant to subdivision (c). (h) (1) On December 31, 2023, and annually thereafter, the department shall report to the Legislature all defensible space data collected pursuant paragraph (2) of subdivision (c). The report may include information on the proportion of unique parcels that were inspected, the degree of compliance with requirements set forth in Section 4291, any enforcement actions that may have been taken for noncompliant parcels, and the proportion of parcels that were found to be in compliance across jurisdictions. At minimum, the report shall include data with sufficient detail to facilitate comparisons of community compliance with the requirements of Section 4291 between local governmental entities qualified to conduct defensible space assessments pursuant to this section and local governmental entities that are not. (2) A report submitted pursuant to this subdivision shall be submitted in compliance with Section 9795 of the Government Code.

(i) This section shall remain in effect only until January 1, 2026, and as of that date is repealed.

SECTION H104—CALIFORNIA CODE OF REGULATIONS, TITLE 14, DIVISION 1.5

H104.1 Subchapter 2 State Minimum Fire Safe Regulations.

1270.01 Definitions.
CWUIC § 6-4 High relevance — show source text
structure.

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FIRE PROTECTION REQUIREMENTS

SECTION 604—MAINTENANCE OF DEFENSIBLE SPACE

604.1 General. Hazardous vegetation and fuels shall be managed to reduce the severity of potential exterior wildfire exposure to build- ings and to reduce the risk of fire spreading to buildings as required by applicable laws and regulations.

Defensible space shall be managed around all buildings and structures in State Responsibility Areas (SRA) as required in Public Resources Code 4291.

604.2 Application. Buildings and structures located in the following areas shall maintain the required hazardous vegetation and fuel management: 1. All unincorporated lands designated as a State Responsibility Area (SRA). 2. Land designated as a Very High Fire Hazard Severity Zone by a city or local agency. 3. Land designated in a city or local agency ordinance as a wildland-urban interface (WUI) area.

604.3 Requirements. Hazardous vegetation and fuels around all buildings and structures shall be maintained in accordance with the following laws and regulations: 1. Public Resources Code, Section 4291.

2. California Code of Regulations, Title 14, Division 1.5, Chapter 7, Subchapter 3, Article 3, Section 1299.03. 3. California Government Code, Section 51182.

4. California Code of Regulations, Title 19, Division 1, Chapter 7, Subchapter 1, Section 3.07.

604.4 Outbuildings. Outbuildings shall have a minimum clearance of 10 feet (3048 mm) down to bare mineral soil in all directions. Vege- tation more than 10 feet (3048 mm) but less than 20 feet (6096 mm) from outbuildings shall be fire-smart vegetation.

604.5 Disposal of flammable vegetation and fuels. The disposal, including burning or removal to a site approved by the local jurisdic- tion in consultation with the fire authority, of flammable vegetation and fuels caused by site, road and driveway construction shall be in accordance with all applicable laws and regulations. [CCR T14 §1276.05]

SECTION 605—SPARK ARRESTORS

605.1 General. Chimneys serving fireplaces, barbecues, incinerators or decorative heating appliances in which solid or liquid fuel is used shall be provided with a spark arrestor. Spark arrestors shall be constructed of woven or welded wire screening of 12 USA standard gage wire (0.1046 inch) (2.66 mm) having openings not exceeding [1] / 2 inch (12.7 mm).

605.2 Net free area. The net free area of the spark arrestor shall be not less than four times the net free area of the outlet of the chimney.

SECTION 606—LIQUEFIED PETROLEUM GAS INSTALLATIONS

606.1 General. The storage of liquefied petroleum gas (LP-gas) and the installation and maintenance of pertinent equipment shall be in accordance with the California Fire Code .

606.2 Location of containers or tanks. LP-gas containers or tanks shall be located within the defensible space in accordance with the California Fire Code .
CWUIC § 603.4.1 High relevance — show source text
603.4.1 Shrubs. All new plantings of shrubs shall comply with the following: 1. Shrubs shall not exceed 6 feet (1829 mm) in height. 2. Groupings of shrubs are limited to a maximum aggregate diameter of 10 feet (3048 mm). 3. Shrub groupings shall be separated from other groupings a minimum of 15 feet (4572 mm). 4. Shrub groupings shall be separated from structures a minimum of 30 feet (9144 mm). 5. Where shrubs are located below or within a tree’s drip line, the lowest tree branch shall be a minimum of three times the height of the understory shrubs or 10 feet (3048 mm), whichever is greater.

603.4.2 Trees. Trees shall be managed as follows within the 30-foot zone (9144 mm) of a structure: 1. New trees shall be planted and maintained so that the tree’s drip line at maturity is a minimum of 10 feet (3048 mm) from any combustible structure. 2. The horizontal distance between crowns of new trees and crowns of adjacent trees shall not be less than 10 feet (3048 mm). 3. Existing trees shall be trimmed to provide a minimum separation of 10 feet (3048 mm) away from chimney and stovepipe outlets per California Code of Regulations, Title 14, Section 1299.03.

603.4.2.1 Nonfire-smart vegetation. New trees not classified as fire-smart vegetation, such as conifers, palms, pepper trees and eucalyptus species, shall be permitted provided the tree is planted and maintained in accordance with one of the following: 1. The tree is planted so that the tree’s drip line at maturity is a minimum of 30 feet (9144 mm) from an applicable building. 2. The tree is planted so that the tree’s drip line at maturity is a minimum of 10 feet (3048 mm) from any combustible struc- ture, and is well pruned and maintained so as not to form a means of rapidly transmitting fire from other nearby vegetation to the structure or from the structure to nearby vegetation or to interrupt the advance of embers toward a

structure.

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FIRE PROTECTION REQUIREMENTS

SECTION 604—MAINTENANCE OF DEFENSIBLE SPACE

604.1 General. Hazardous vegetation and fuels shall be managed to reduce the severity of potential exterior wildfire exposure to build- ings and to reduce the risk of fire spreading to buildings as required by applicable laws and regulations.

Defensible space shall be managed around all buildings and structures in State Responsibility Areas (SRA) as required in Public Resources Code 4291.

604.2 Application. Buildings and structures located in the following areas shall maintain the required hazardous vegetation and fuel management: 1. All unincorporated lands designated as a State Responsibility Area (SRA). 2. Land designated as a Very High Fire Hazard Severity Zone by a city or local agency. 3. Land designated in a city or local agency ordinance as a wildland-urban interface (WUI) area.
CWUIC § 1.5 High relevance — show source text
GENERAL REQUIREMENTS

Any person that owns, leases, controls, operates or maintains any building or structure in, upon or adjoining any mountainous area or forest-covered lands, brush covered lands or grass-covered lands, or any land which is covered with flammable material, shall at all times do all of the following:

(1) Maintain around and adjacent to such building or structure a firebreak made by removing and clearing away, for a distance of not less than 30 feet on each side thereof or to the property line, whichever is nearer, all flammable vegetation or other combustible growth. This section does not apply to single specimens of trees, ornamental shrubbery or similar plants which are used as ground cover, if they do not form a means of rapidly transmitting fire from the native growth to any building

or structure.

(2) Maintain around and adjacent to any such building or structure additional fire protection or firebreak made by removing all bush, flammable vegetation or combustible growth which is located from 30 feet to 100 feet from such building or structure or to the property line, whichever is nearer, as may be required by the enforcing agency if he finds that, because of extra hazardous conditions, a firebreak of only 30 feet around such building or structure is not sufficient to provide reasonable fire safety. Grass and other vegetation located more than 30 feet from such building or structure and less than 18 inches in height above the ground may be maintained where necessary to stabilize the soil and prevent erosion.

(3) Remove that portion of any tree which extends within 10 feet of the outlet of any chimney or stovepipe.

(4) Cut and remove all dead or dying portions of trees located adjacent to or overhanging any building.

(5) Maintain the roof of any structure free of leaves, needles or other dead vegetative growth.

(6) Provide and maintain at all times a screen over the outlet of every chimney or stovepipe that is attached to any fireplace, stove or other device that burns any solid or liquid fuel. The screen shall be constructed of nonflammable material with openings of not more than [1] / 2 inch in size.

(7) Vegetation around all applicable buildings and structures shall be maintained in accordance with the following laws and regulations:

(A) Public Resources Code Section 4291.

(B) California Code of Regulations Title 14 - Natural Resources, Division 1.5 - Department of Forestry and Fire Protection, “General Guideline to Create Defensible Space.”

(C) California Government Code Section 51182.

(D) California Code of Regulations, Title 24, Part 9.

304.1.4 Space underneath seats. Spaces underneath grandstand and bleacher seats shall be kept free from combustible and flammable materials. Except where enclosed in not less than 1-hour fire-resistance-rated construction in accordance with the California Building Code .

304.1.4.1 Spaces underneath grandstands and bleachers. Spaces underneath grandstands and bleachers shall not be occupied or utilized for purposes other than means of egress except where equipped with an automatic sprinkler system in accordance with Section 903.2.1.5.1, or separated with fire barriers and horizontal assemblies in accordance with Section 1030.1.1.1.

304.2 Storage. Storage of combustible rubbish shall not produce conditions that will create a nuisance or a hazard to the public health, safety or welfare.

CWUIC § 1.5 High relevance — show source text

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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 6	Fire protection requirements	Fire protection requirements	Fire protection requirements	Fire protection requirements	Fire protection requirements	Fire protection requirements	Fire protection requirements	Fire protection requirements	Fire protection requirements	Fire protection requirements
603.4.1	Shrubs	Y			4906.4.1
603.4.2	Trees	Y			4906.4.2	1299.03	3.07(b)(3)
603.4.2.1	Nonfire-smart vegetation	Y			4906.4.2.1
604	Maintenance of defensible space	Y			4907
604.1	General	Y			4907.1					4291
604.2	Application	Y			4907.2
604.3	Buildings and structures	Y		701A.3.1	4907.3
604.4	Outbuildings	Y				1299.03(c)(1)
604.5	Disposal of flammable vegetation and fuels	Y				1276.05
605	Spark arrestors	Y		2113.9.2			3.07(b)(6)
605.1	General	Y		2113.9.2 #2 2113.9.2 #3	605.8.2
605.2	Net free area	Y		2113.9.2 #1
606	Liquefied petroleum gas installations	Y			6103
606.1	General	Y			6103.2.1
606.2	Location of contain- ers or tanks	Y			6104.3
606.3	Clear area	Y				1299.03(c)(1)
607	Storage of firewood and combustible materials	Y
607.1	General	Y				1299.03(a)(3) 1299.03(b)(2)(c)
607.2	Storage for off-site use	Y	607.2
608	Building siting and setbacks	Y				1276.00
608.1	Intent	Y				1276.01
_608.

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.

2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 6-3

CWUIC § 3.2.2 Medium relevance — show source text

3.2.2|Minimum clearance
to be maintained|N|||||||4293
4296|| |A102.3.2.3|Electrical power line
emergencies|N||||||||| |A102.4|Correction of
condition|N||||||||| |A103|Access restrictions|N||||||||| |A103.1|Restricted entry to
public lands|N||||||||| |A103.2|Trespassing on
posted private
property|N||||||||| |A103.2.1|Signs|N||||||||| |A103.2.2|Trespassing|N||||||||| |A103.3|Use of fire roads and
defensible space|N||||||||| |A103.3.1|Obstructions|N||||||||| |A103.4|Use of motorcycles,
motor scooters, ultra-
light aircraft and
motor vehicles|N||||||||| |A103.5|Tampering with
locks, barricades,
signs and address
markers|N|||||||||

2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX H-33

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 A	General requirements	General requirements	General requirements	General requirements	General requirements	General requirements	General requirements	General requirements	General requirements	General requirements
A103.5.1	Gates, doors, barriers and locks	N
A104	Ignition source control	N
A104.1	General	N
A104.2	Objective	N
A104.3	Clearance from igni- tion sources	N
A104.4	Smoking	N
A104.5	Equipment and devices generating heat, sparks or open flames	N
A104.6	Fireworks	N
A104.6.1	Authority to seize	N
A104.7	Outdoor fires	N
A104.7.1	General	N
A104.7.2	Permits	N
A104.7.3	Restrictions	N
A104.8	Incinerators, outdoor fireplaces, perma- nent barbecues and grills	N
A104.8.1	Maintenance	N
A104.

CWUIC § 4902.1 Medium relevance — show source text

01(i)||||| ||Exterior wall assembly|Y||702A||||||| ||Exterior wall covering|Y||702A||||||| ||Fire chief|Y||||||||| ||Fire code official|Y|||202|||||| ||Fire flow calculation
area|Y||||||||| ||Fire hazard severity
zones|Y||702A|4902.1|||2201||| ||Fire protection plan|Y||702A|4902.1|||||| ||Fire weather|Y||||||||| ||Fire-resistance-rated
construction|Y||||||||| ||Fire-smart vegetation|Y|||4902.1|1271.01||||| ||Flame spread index|Y||||||||| ||Fuel|Y||||||||4291(a)(1)(A)| ||Fuel break_(T14)|Y||||1270.01(n)||||| ||Fuel modification|Y||||||||| ||Fuel mosaic|Y||||||||| ||Fuel-loading|Y||||||||| ||Green belt(T14)|Y||||1270.01(o)||||| ||Greenways (T14)|Y||||1270.01(p)||||| ||Hammerhead/T (T14)|Y||||1270.01(q)||||| ||Hazardous land use
(T14)_|Y||||1270.01(r)||||| ||Hazardous materials|Y||||||||| ||Heavy timber
construction|Y||||||||| ||Ignition-resistant
building material|Y||||||||| ||Local responsibility
area (LRA)|Y||702A|4902.1|||||| ||Log wall construction|Y|||||||||

2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX H-25

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.

Frequently asked questions

What if my property line is closer than 100 ft?

You are required to provide defensible space up to the property line; fuel modification is not required beyond the property line unless state/local law or a written agreement allows it. PRC § 4291.

Does the 100‑ft rule apply everywhere in California?

PRC § 4291 applies where the statute applies (notably in SRA and similar settings); CWUIC § 604.2 clarifies application to SRA, local VHFHSZs, and local WUI ordinances. Check local ordinances — they may be more restrictive.

How close can trees be to a chimney?

Trim and remove the portion of any tree that extends within 10 feet of the chimney or stovepipe outlet (PRC § 4291).

Are single specimen trees allowed inside defensible space?

Yes — single specimens may remain if they are well‑pruned and maintained so they do not form a rapid fire transmission path to or from the structure (PRC § 4291).

Can an insurer require more than 100 ft?

Yes; an insurer may require a greater distance if a qualified fire expert finds it necessary and no feasible alternatives exist; such increases still must comply with property‑line and legal limits in § 4291.

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California Wildland-Urban Interface Code