Santa Rosa, CA Accessory Structures: Garage Conversions (2026)
Garage conversion rules in Santa Rosa, CA, sometimes called garage-to-ADU or accessory living unit conversions, govern permits, ceiling height, egress, and parking replacement.
Key Facts
- Parking replacement required?
- No (per E.10.h)
- Setback for converted existing garage
- No setback required if converted to ADU with independent exterior access
- Setback for ADU above existing garage
- 5 ft from side and rear property lines
- Max size of converted detached accessory structure ADU
- 1,200 sq ft
- Combined height (ADU over garage)
- 27 ft max
- Approval process
- Ministerial, 60-day decision deadline
- Utility connection fees
- Waived for internal conversions and ADUs ≤750 sq ft
- Public improvement requirements
- Waived for internal conversion of existing residential square footage (Sec. 18-12.015(A)(3))
- Fire sprinklers
- Required if conversion + remodel/addition exceeds 50% of existing total floor area
- Short-term rental of converted unit
- Prohibited (rentals <30 days not allowed)
Summary
Santa Rosa permits garage-to-ADU conversions ministerially under Zoning Code Section 20-42.130 with no replacement parking required and no setback required for existing legally constructed garages converted to an ADU with independent exterior access. Conversion to non-habitable storage requires a standard building permit, while conversion to habitable space (ADU or JADU) follows the city's 2020 ADU ordinance and California Government Code Sections 65852.2 and 65852.22.
c. No setback shall be required for an existing legally constructed living area, garage, or other accessory structure that is converted to an accessory dwelling unit with independent exterior access from an existing or proposed residence. A setback of five feet from the side and rear property lines is required for an accessory dwelling unit constructed above an existing legally constructed garage... 10. Parking. One off-street parking space is required for an accessory dwelling unit, except as set forth below... h. No replacement off-street parking spaces are required when an accessory dwelling unit is created through the conversion or demolition of a garage, carport or covered parking structure... 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. b. When an accessory dwelling unit is located above an existing or proposed garage, the entire combined structure shall not exceed 27 feet in height.
Full Breakdown
c, 'No setback shall be required for an existing legally constructed living area, garage, or other accessory structure that is converted to an accessory dwelling unit with independent exterior access from an existing or proposed residence. c). 015(A)(3). 2 if it complies with all development standards. b). b(1)). 3 and require a standard building permit.
Violations & Fines
Converting a garage to habitable use (kitchen, bathroom, sleeping space, conditioned living area) without a Building Permit and ADU/JADU approval under Section 20-42.130 is a code violation that may result in stop-work orders, demolition orders, and double permit fees. Unpermitted conversions are also subject to the ADU Enforcement Deferral Program (Policy 2530) only for units constructed before March 3, 2020; later unpermitted conversions face full enforcement.
Frequently Asked Questions
Do I lose required off-street parking if I convert my garage to an ADU in Santa Rosa?
Can my existing garage be too close to the property line to convert to an ADU?
Will I need to install fire sprinklers when converting my garage to an ADU?
How tall can I build above my existing garage?
Sources & Official References
Other rules in Santa Rosa
California rules heatmap·Compare Santa Rosa to another location·View the California accessory structures overview
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Garage Conversions in Nearby Cities
How other cities in Sonoma County handle garage conversions.