Building Safety in Marin County, CA (2026)
8 county-level rules, plus city-specific rules for 1 city in Marin County, California.
Verified from official government sources
Fire Sprinkler Requirements
Fire Code § 903.2.3 requires an automatic sprinkler system throughout every one- and two-family dwelling in unincorporated Marin regardless of square footage, and in every mobile or manufactured home with two or more units. New construction is covered broadly by § 903.2.1.
Marin County Requires Sprinklers in All Homes
Heavy RestrictionsMarin County Code of Ordinances § 903.2.3 (Fire Code)
Section 903.2.3 Group R-3. An automatic sprinkler system installed in accordance with Section 903.3.1.3 shall be permitted in Group R-3 occupancies and shall be provided throughout all one- and two-family dwellings regardless of square footage in accordance with the California Residential Code. An automatic sprinkler system shall be installed in all mobile homes, manufactured homes and multi-fa...
Childcare Center Rules
Marin County child day-care centers in unincorporated areas must clear a Use Permit and meet building-safety standards written specifically for children on site. Marin County Code of Ordinances § 22.32.050(C)(2) requires a six-foot fence or wall around outdoor play areas, restricts exterior lighting to shielded, downward-directed, low-wattage safety fixtures, and bars new swimming pools or spas once the center is established.
Marin County Child Day-Care Facility Safety Rules
Significant RestrictionsMarin County Code of Ordinances § 22.32.050(C)(2)
2.Standards for child day-care centers. The following standards apply to child day-care centers in addition to the standards in Subsection 22.32.050.C.2:a.Fencing. A six-foot high fence or wall shall be constructed on all property lines or around the outdoor activity areas, except in the front yard or within a traffic safety visibility area. All fences or walls shall provide for safety with con...
Anti-Mansionization
In the Tamalpais Community Plan Area of unincorporated Marin, Development Code Section 22.30.060 caps the maximum adjusted Floor Area Ratio at 30 percent of lot area for new homes on vacant lots and for "substantial remodels" (additions of 25 percent or more) on steep or undersized lots. New construction on a vacant lot with 25-percent-plus average slope needing Design Review is capped at the lesser of 7,000 square feet or that FAR figure.
Marin County Caps House Size in Tamalpais Area
Some RestrictionsMarin County Code of Ordinances § 22.30.060
For lots within the Tamalpais Community Plan Area, the following maximum adjusted Floor Area Ratio standards shall apply to: (1) new residential construction proposed on vacant lots; (2) substantial remodels proposed on properties with a slope of 25% or greater; or (3) substantial remodels proposed on properties that do not comply with the minimum lot area requirements. For purposes of this sec...
Green Building Code
Marin County Code Section 19.04.110 adopts local green building measures on top of the 2025 California Green Building Standards Code and 2025 California Energy Code, requiring covered projects to meet CALGreen Tier 1 and electrification standards tied to Marin's wildfire, sea-level-rise, and seismic risks. The Community Development Agency's Building and Safety Division enforces these mandatory measures.
Marin County Green Building Standards Code Requirements
Some RestrictionsMarin County Code of Ordinances § 19.04.110
The purpose of this chapter is to meet or exceed all applicable mandatory measures of the 2025 California Green Building Standards Code (Title 24, Part 11) and 2025 California Energy Code (Title 24, Part 6) of the California Code of Regulations. Pursuant to Health and Safety Code Sections 17958.7 and 18941.5, the Marin County Board of Supervisors hereby finds the following green building modifi...
Carbon Monoxide Detectors
Marin County Code § 19.14.020(3) requires State Fire Marshal-compliant carbon monoxide alarms in every existing dwelling unit that has a fuel-fired appliance, a fireplace, or an attached garage, verified as a condition of final inspection on any building permit issued after July 1, 2023.
Marin County Carbon Monoxide Alarm Rule
Some RestrictionsMarin County Code of Ordinances § 19.14.020(3)
For all building permits issued after July 1, 2023: Pursuant to California Health and Safety Code section 17926(a) and California Residential Code section R311.2, carbon monoxide alarms shall be installed and verified in all existing dwelling units where either or both of the following conditions exist: 1) The dwelling unit contains a fuel-fired appliance or fireplace; or 2) The dwelling unit h...
Electrical Permits
Marin County Code Section 19.04.010 adopts the 2025 California Electrical Code, which incorporates the 2023 National Electrical Code, as the standard governing all electrical permits in the unincorporated county. The Building and Safety Division of the Community Development Agency reviews plans, issues permits, and inspects electrical work under this adopted code.
Marin County Adopts 2025 California Electrical Code
Some RestrictionsMarin County Code of Ordinances § 19.04.010(3)
(3)The 2025 edition of the California Electrical Code, known as California Code of Regulations, Part 3 of Title 24, incorporating the 2023 edition of the "National Electrical Code" published by the National Fire Protection Association, with exceptions, additions and deletions as provided in this title.
Plumbing Permits
Marin County Code Section 19.04.010 adopts the 2025 California Plumbing Code, built on the 2024 Uniform Plumbing Code, as the standard for every plumbing permit issued in the unincorporated county. The Building and Safety Division of the Community Development Agency reviews plans and inspects plumbing installations under this adopted code.
Marin County Adopts 2025 California Plumbing Code
Some RestrictionsMarin County Code of Ordinances § 19.04.010(5)
(5)The 2025 edition of the California Plumbing Code, known as California Code of Regulations, Part 5 of Title 24, incorporating the 2024 edition of the "Uniform Plumbing Code" as published by the International Association of Plumbing and Mechanical Officials, with exceptions, additions, and deletions as provided in this title.
Building Inspections
Marin County Code § 19.14.020 adds a countywide step to the final inspection of any building permit issued after July 1, 2023: proof that the project meets a checklist of state life-safety and water-conservation requirements before the county will close out the permit.
Marin County Final Inspection Verification Rules
Some RestrictionsMarin County Code of Ordinances § 19.14.020
Prior to, and as a condition of the issuance and final inspection of any maintenance or minor improvement permits (i.e., permits not requiring the submittal of plans and plan review approval prior to permit issuance), the permit applicant must demonstrate compliance with the following requirements by submitting a signed affirmative declaration indicating compliance with this chapter to the buil...
Building Safety by City in Marin County
1 cities in Marin County have their own building safety rules. Each link goes to that city's dedicated page with code citations.
All Marin County ordinances
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