Accessory Structures in Sonoma, CA (2026)
6 verified accessory structures rules for Sonoma, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
The City of Sonoma caps ADU-permit-track accessory dwelling units at 850 square feet for a studio or one bedroom and 1,000 square feet for two bedrooms, with a four-foot minimum side and rear setback and height limits from 16 to 25 feet depending on story count. State ADU law overrides any local limit that conflicts.
City of Sonoma Accessory Dwelling Unit Zoning Rules
Some RestrictionsSonoma Municipal Code § 19.45.040(A), (D)
A. Maximum Size. 1. The maximum size of a detached or attached ADU requiring an ADU permit is 850 square feet for a studio or one-bedroom unit and 1,000 square feet for a unit with two bedrooms. No more than two bedrooms are allowed. 2. Application of other development standards may further limit the size of the ADU, but the application of development standards that impose limits on lot coverag...
ADU Impact Fees
The City of Sonoma charges no impact fee on an ADU under 750 square feet. Larger ADUs pay a fee scaled to the ADU's share of the primary dwelling's floor area, and converted ADUs sharing an existing utility connection avoid a new connection fee unless built alongside a new primary home.
City of Sonoma ADU Impact & Utility Fees
Light RestrictionsSonoma Municipal Code § 19.45.040(J)(1)
J. Fees. 1. Impact Fees. a. No impact fee is required for an ADU that is less than 750 square feet in size. b. Any impact fee that is required for an ADU that is 750 square feet or larger in size must be charged proportionately in relation to the square footage of the primary dwelling unit (e.g., the floor area of the primary dwelling, divided by the floor area of the ADU, times the typical fee...
ADU Owner Occupancy
The City of Sonoma requires owner-occupancy for every junior accessory dwelling unit: the titleholder must live in either the primary home or the JADU as a legal domicile. Standard ADUs permitted since January 1, 2020 carry no owner-occupancy requirement, but older ADUs stay bound by whatever rule applied when they were permitted.
City of Sonoma ADU/JADU Owner-Occupancy Rule
Some RestrictionsSonoma Municipal Code § 19.45.030(E)
E. Owner Occupancy. 1. All ADUs permitted before January 1, 2020, are subject to the owner-occupancy requirement that was in place when the ADU was permitted. 2. All JADUs are subject to an owner-occupancy requirement. A natural person with legal or equitable title to the property must reside on the property, in either the primary dwelling or JADU, as the person's legal domicile and permanent r...
ADU Rental Restrictions
An accessory dwelling unit or junior accessory dwelling unit in the City of Sonoma cannot be rented for a term shorter than 30 days, which bars vacation-rental use of ADUs outright. An ADU may be rented long-term, but it can never be sold or conveyed apart from the primary lot and dwelling.
City of Sonoma ADU 30-Day Minimum Rental Term
Some RestrictionsSonoma Municipal Code § 19.45.030(B)-(C)
B. Rental Term. No ADU or JADU may be rented for a term that is shorter than 30 days. C. No Separate Conveyance. An ADU or JADU may be rented, but no ADU or JADU may be sold or otherwise conveyed separately from the lot and the primary dwelling (in the case of a single-family lot) or from the lot and all of the dwellings (in the case of a duplex or multifamily lot).
Shed & Carport Rules
A single portable storage shed under 120 square feet and no taller than 8 feet needs no building permit or land use permit in a City of Sonoma residential zone, as long as it sits outside the required front and street-side setbacks, under Sonoma Municipal Code § 19.03.030(B)(6). Bigger or taller sheds, or ones placed inside a setback, fall under the ordinary building and zoning review process instead.
City of Sonoma Backyard Shed Rules
Some RestrictionsSonoma Municipal Code § 19.03.030(B)(6)
6. Small Residential Accessory Structures (Portable). A single portable structure per lot or unit, including premanufactured storage sheds and other small structures in residential zoning districts that: a. Are exempt from building permit requirements in compliance with SMC Title 14 and the Uniform Building Code; b. Are less than 120 square feet in gross floor area and no more than eight feet i...
Garage Conversions
When a City of Sonoma property owner converts or demolishes an existing garage, carport, or covered parking structure to build a second unit under the city's SB 9 two-unit residential program, SMC 19.41.150(A)(8)(d) requires at least one replacement parking space, covered or uncovered, for each unit.
Sonoma Garage Conversion Parking Rule
Some RestrictionsSonoma Municipal Code § 19.41.150(A)(8)(d)
8. Off-Street Parking. ... a. One covered or uncovered off-street parking space is required per dwelling unit in a two-unit residential project, except as exempted below. ... ... c. Tandem parking is prohibited. Each unit must have its own parking space which can be accessed without crossing over or encroaching upon the other unit’s parking space. d. When an existing garage, carport, or other c...
Looking for Sonoma County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Sonoma city rules.
Accessory Structures in Sonoma County →