Contra Costa County Municipal Code Ch. 722-4 Wildland-Urban Interface Code

The 2025 California Wildland-Urban Interface Code (California Code of Regulations, Title 24, Part 7), including Chapters 1—7, Appendix A, Appendix B, Appendix C, Appendix F, Appendix G, and Appendix H, as amended the changes, additions, and deletions set forth in this chapter, is adopted by this reference as though fully set forth herein as the Wildland-Urban Interface Code of Contra Costa County, the Crockett-Carquinez Fire Protection District, and the Contra Costa County Fire Protection District. The provisions of this chapter are controlling and enforceable within the limits of each jurisdiction.

(Ord. No. 2025-15, § 2, 12-9-25)

The 2025 California Wildland-Urban Interface Code is amended by the changes, additions, and deletions set forth in this section. Chapter and section numbers used below are those of the 2025 California Wildland-Urban Interface Code ("WUIC"):

(a) Section 1.1.2 (Purpose) of WUIC Chapter 1 (Administration) is amended to read:

1.1.2 Purpose. The purpose of this code is to: (1) establish minimum requirements to reduce the likelihood of life and property loss due to a wildfire through the use of performance and prescriptive requirements for construction and development in all Fire Hazard Severity Zones in State Responsibility Areas (SRA), and Local Responsibility Areas (LRA) designated as a Very High or High Fire Hazard Severity Zone; (2) increase the ability of buildings located in any Fire Hazard Severity Zone within State Responsibility Areas (SRA), or Wildland-Urban Interface (WUI) Areas, to resist the intrusion of flames or embers projected by a fire; and (3) contribute to a systematic reduction in conflagration losses and reduce the likelihood of life and property loss due to a wildfire.

(b) Section 101.1 (Title) of WUIC Chapter 1 (Administration) is amended to read:

[A] 101.1 Title. These regulations shall be known as the California Wildland-Urban Interface Code of Contra Costa County, the Crockett-Carquinez Fire Protection District, and the Contra Costa County Fire Protection District, hereinafter referred to as "this code."

(c) Section 101.3.1 (Application) of WUIC Chapter 1 (Administration) is amended to read:

101.3.1 Application. New buildings and structures 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, located in any of the following:

A. All lands designated by the State Board of Forestry and Fire Protection as State Responsibility Area (SRA).

B. Lands in Local Responsibility Area (LRA) identified by the State Fire Marshal as High or Very High Fire Hazard Severity Zone.

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

D. Land designated as a Wildland-Urban Interface Area by cities and other local agencies.

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.

(d) Section [A]101.5 (Additions or alterations) of WUIC Chapter 1 (Administration) is amended to read:

[A] 101.5 - Additions or alterations.

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

Exceptions:

1. The existing building or structure must meet any provisions of this code that expressly apply to an existing building or structure retroactively.

2. If a substantial addition or substantial alteration is made to any existing building or structure, the existing building or structure, and the substantial addition or substantial alteration, must comply with all requirements of this code.

B. 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: (a) will cause the existing building or structure to become structurally unsafe or overloaded; (b) will not provide adequate access in compliance with the provisions of this code or will obstruct existing exits or access; (c) will create a fire hazard; (d) will reduce required fire resistance; or (e) will otherwise create conditions dangerous to human life.

(e) Section 202 (Definitions) of WUIC Chapter 2 (Definitions) is amended by adding the following two new definitions, to read:

Substantial Addition. Any change to an existing building or structure that meets both of the following criteria:

(a) adds gross floor area that exceeds fifty percent of the gross floor area of the existing building or structure; and

(b) results in the building or structure and the addition having a combined new gross floor area of 5,000 square feet or more.

Substantial Alteration. Any change to an existing building or structure that meets both of the following criteria within a one-year period:

(a) The removal of fifty percent or more of the linear length of any interior or exterior wall of the building or structure; and

(b) The removal and replacement of fifty percent or more of the area of the building or structure's roof.

(f) Section 508 (Non-Combustible Fences in Wildland-Urban Interface Fire Areas) is added to WUIC Chapter 5 (Special Building Construction Regulations), to read:

Section 508 - Non-Combustible Fences in Wildland-Urban Interface Areas.

508.1 Scope. Unless an exception applies, new residential subdivisions must satisfy the fencing requirements of Sections 508.2 and 508.3, if the subdivision meets both of the following criteria: (a) the subdivision includes 30 or more dwelling units; and (b) any portion of the subdivision is located within or abuts a designated Wildland-Urban Interface Area.

508.2 General Requirement. All fencing regulated by this section shall be constructed of non-combustible materials, or materials approved for a minimum one-hour fire-resistance rating. For purposes of this requirement, fencing includes fence posts, rails, pickets, panels, post caps, gates, decorative features, and appurtenances.

508.3 Location.

A. If a lot or any portion of a lot is located within a Wildland-Urban Interface Area, all perimeter fencing within that lot and all fencing within 30 feet of a structure on that lot or an adjacent lot shall comply with Section 508.2.

B. Any fencing that abuts a Wildland-Urban Interface Area shall comply with Section 508.2, even if the lot on which the fencing is located is not within a Wildland-Urban Interface Area.

C. Any fencing located within five feet of a structure on any lot must comply with Section 508.2, regardless of whether any portion of the lot is located within or adjacent to a Wildland-Urban Interface Area.

508.4 Exception. Temporary fencing for construction or erosion control is not required to comply with this Section 508, provided it is removed within 180 days of installation.

(Ord. No. 2025-15, § 2, 12-9-25)

Unless superseded and expressly repealed, references in city forms, documents, and regulations to the chapters and sections of any prior version of the Wildland-Urban Interface Code of Contra Costa County, the Crockett-Carquinez Fire Protection District, and the Contra Costa County Fire Protection District shall be construed to apply to the corresponding provisions contained within the 2025 Wildland-Urban Interface Code of Contra Costa County, the Crockett-Carquinez Fire Protection District, and the Contra Costa County Fire Protection District.

(Ord. No. 2025-15, § 2, 12-9-25)

The Contra Costa County Board of Supervisors declares that if any section, paragraph, sentence, or word of this chapter, or of the 2025 California Wildland-Urban Interface Code as adopted and amended herein, is declared for any reason to be invalid, it is the intent of the Contra Costa County Board of Supervisors that it would have passed all other portions or provisions of this ordinance independent of the elimination here from any portion or provision as may be declared invalid.

(Ord. No. 2025-15, § 2, 12-9-25)

If requirements more restrictive than those in this chapter are adopted by the city of Antioch, Bay Point, Bethel Island, Brentwood, Byron, Clayton, Concord, Discovery Bay, Hercules, Knightsen, Lafayette, Martinez, Oakley, Pittsburg, Pleasant Hill, San Pablo, or Walnut Creek, or the County of Contra Costa, those more-restrictive requirements will apply only within the jurisdiction adopting those requirements.

(Ord. No. 2025-15, § 2, 12-9-25)