Santa Rosa, CA Accessory Structures: ADU Rules (2026)
ADU rules in Santa Rosa, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Max detached ADU size
- 1,200 sq ft habitable space
- Max JADU size
- 500 sq ft (+150 sq ft allowed for separate entrance)
- Side/rear setback (one-story)
- 4 ft minimum
- Side/rear setback (two-story)
- 8 ft minimum
- Height limit (one-story)
- 16 ft
- Height limit (two-story)
- 27 ft
- Parking required
- 1 space (multiple exemptions)
- Owner occupancy (ADU)
- Not required
- Owner occupancy (JADU)
- Required by recorded deed restriction
- Permit approval
- Ministerial, 60-day decision deadline
- Short-term rentals
- Prohibited (<30-day terms not allowed)
- Number per single-family lot
- 1 ADU + 1 JADU
Summary
Santa Rosa allows one ADU plus one JADU on single-family lots under Zoning Code Section 20-42.130, adopted by urgency Ordinance on March 3, 2020 to align with California Government Code Sections 65852.2 and 65852.22. Detached ADUs are capped at 1,200 sq ft with 4-ft side/rear setbacks and a 16-ft (one-story) or 27-ft (two-story) height limit; JADUs are capped at 500 sq ft and must sit entirely within the existing single-family dwelling walls.
20-42.130 Accessory dwelling units. Accessory dwelling units shall comply with the requirements of this Section, where allowed by Division 2 (Zoning Districts and Allowable Land Uses). A. Purpose. The provisions of this Section are intended to set standards, in compliance with California Government Code Sections 65852.2, and 65852.22, for the development of accessory dwelling units so as to increase the supply of smaller and affordable housing while ensuring that such housing remains compatible with the existing neighborhood. B. General requirements. An accessory dwelling unit: 1. May be located on any lot that allows a single-family or multifamily residential use and includes a proposed or existing dwelling. 2. Is not subject to the density requirements of the General Plan, but shall otherwise be consistent with the General Plan text and diagrams. 3. Shall not be allowed on, or adjacent to, real property that is listed in the California Register of Historic Places. 4. Shall not be used for rentals with terms of less than 30 days. 5. Shall not be sold separate from the primary residence... E. Development standards. An accessory dwelling unit permit shall be issued only if the unit complies with the following development standards: 1. General. No development standards shall be applied that would prohibit at least an 800 square foot accessory dwelling unit that is at least 16 feet in height with four-foot side and four-foot rear setbacks to be constructed in compliance with all other local development standards... 3. Maximum floor area. a. New detached unit. No newly constructed detached accessory dwelling unit may contain habitable space in excess of 1,200 square feet... 4. Height limit. a. A one-story accessory dwelling unit shall not exceed a maximum height of 16 feet. A two-story accessory dwelling unit shall not exceed a maximum height of 27 feet. No accessory dwelling unit shall exceed 27 feet in height.
Full Breakdown
130 was rewritten by the City Council on March 3, 2020 as an urgency measure after Senate Bill 13 and Assembly Bills 68, 881, 670, and 587 voided the city's prior ADU rules on January 1, 2020. The ordinance preserves city-specific protections for hillsides, Historic Preservation Districts, and creekside setbacks while ministerially approving any application that complies with the development standards. 3). c). 4). 10). Owner-occupancy is not required for ADUs; the City's deferred enforcement and the deletion of owner-occupancy language reflect 2019 state legislation.
JADUs (Subsection F) max 500 sq ft, must be within existing single-family residence walls, require deed restrictions filed with Sonoma County recording owner-occupancy and prohibiting separate sale, and require no off-street parking.
Violations & Fines
Construction of an ADU or JADU without a building permit constitutes a Santa Rosa Municipal Code violation enforced by Code Enforcement. The City offers an ADU Enforcement Deferral Program (Policy 2530) for certain unpermitted units built before March 3, 2020. Lack of compliance with JADU deed restrictions voids the JADU approval and may result in legal action against the property owner per Subsection G.3 of the ordinance.
Frequently Asked Questions
Do I need owner-occupancy to build an ADU in Santa Rosa?
Can I rent my Santa Rosa ADU short-term?
How tall can a two-story ADU be?
Do I need to add parking when converting my garage to an ADU?
Sources & Official References
Other rules in Santa Rosa
How Santa Rosa compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Santa Rosa to another location·View the California accessory structures overview
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ADU Rules in Nearby Cities
How other cities in Sonoma County handle adu rules.