Sonoma, CA Building Safety: Fire Sprinkler Requirements (2026)
Key Facts
- Mandate scope
- All new one- and two-family dwellings
- ADU exemption size cap
- 1,200 sq. ft.
- Design standard
- R313.3 or NFPA 13D
- Manufactured home standard
- CCR Title 25 § 4302
- Code currency
- Ord. 13-2025, Dec. 3, 2025
Summary
The City of Sonoma requires an automatic fire sprinkler system in every new one- and two-family dwelling under Sonoma Municipal Code § 14.10.020(D). Existing homes without sprinklers adding an addition are excused, and a detached accessory dwelling unit up to 1,200 square feet is exempt if the primary home itself lacks sprinklers.
Revise subsection R313.2 in its entirety, including the exceptions and subsection R313.2.1, and replace to read as follows:R313.2 One- and two-family dwellings automatic fire sprinkler systems. An automatic residential fire sprinkler system shall be installed in one- and two-family dwellings in accordance with the Fire Code as amended by the City of Sonoma. Exceptions: 1. An automatic residential fire sprinkler system shall not be required for additions or alterations to existing buildings that are not already provided with an automatic residential sprinkler system unless otherwise required by the Fire Code as amended by the City of Sonoma. 2. Accessory Dwelling Unit, provided that all of the following are met: 2.1 The unit meets the definition of an Accessory Dwelling Unit as defined in the Government Code Section 65852.2. 2.2 The existing primary residence does not have automatic fire sprinklers. 2.3 The accessory detached dwelling unit does not exceed 1,200 square feet in size. 2.4 The unit is on the same lot as the primary residence.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 13-2025, passed December 3, 2025).
Full Breakdown
2 of the 2025 California Residential Code in its entirety for the City of Sonoma. The rule states plainly that an automatic residential fire sprinkler system shall be installed in one- and two-family dwellings in accordance with the Fire Code as amended by the city. Two exceptions follow. First, additions or alterations to an existing building that was never equipped with sprinklers do not trigger a sprinkler retrofit, unless the Fire Code as amended by the City of Sonoma otherwise requires it. 2 definition of an ADU, the existing primary residence does not itself have automatic fire sprinklers, the detached unit does not exceed 1,200 square feet, and the unit sits on the same lot as the primary residence.
3 or NFPA 13D, except that factory-built housing, mobile homes, and manufactured homes follow California Code of Regulations, Title 25, Section 4302 instead. 1, also excuses additions or alterations that do not otherwise trigger a Fire Code sprinkler requirement. 10, current through Ordinance 13-2025 of December 3, 2025.
Violations & Fines
Building a new one- or two-family dwelling, or a non-exempt ADU, without the required fire sprinkler system is a violation of Chapter 14.10 SMC, punishable under § 1.12.010(A)(4) by a fine up to $100 for a first violation, $500 for a second within a year, and $1,000 for a third, and the building official may withhold final permit approval until the system is installed and inspected.
Frequently Asked Questions
Does the City of Sonoma require fire sprinklers in new homes?
Do accessory dwelling units in Sonoma need fire sprinklers?
What sprinkler standard applies to a manufactured home in Sonoma?
Sources & Official References
Other rules in Sonoma
California rules heatmap·Compare Sonoma to another location·View the California building safety overview
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Fire Sprinkler Requirements in Nearby Cities
How other cities in Sonoma County handle fire sprinkler requirements.