Building an ADU in San Rafael
City code and California law · Last reviewed October 9, 2026
The City of San Rafael allows ADUs in any zone that allows homes. A single-family lot can combine one attached or detached ADU, one ADU converted from existing space, and one junior ADU. New detached ADUs can be up to 1,000 sq ft with 4-foot side and rear setbacks, and ADUs under 750 sq ft get several fees waived. San Rafael's ADU ordinance was last updated in 2022, and the city says that where newer state law conflicts with it, state law applies. [1][2]
| ADUs allowed | Yes, in any zone that allows single-family or multifamily homes, with an existing or proposed home [1][2] |
|---|---|
| Number on a single-family lot | One attached or detached ADU + one conversion ADU + one junior ADU [1] |
| Detached ADU size | 150 to 1,000 sq ft [1] |
| Attached ADU size | 1,000 sq ft or 50% of the house, whichever is less; 800 sq ft always allowed [1] |
| Junior ADU | 150 to 500 sq ft, converted inside the house (an attached garage counts) [1] |
| Height | Detached 16 ft (18 ft near major transit, plus 2 ft to match the roof); attached 25 ft or the zone limit if lower [1] |
| Side and rear setbacks | 4 ft for new or expanded ADUs; none for conversions in the same footprint [1] |
| Parking | 1 space per ADU unless within a half-mile walk of transit, a conversion, or another exemption (state law also exempts the state-law ADU types); none for junior ADUs [1][2][3] |
| Owner occupancy | Not for ADUs; for a junior ADU, state law requires it only if the bathroom is shared [2][3] |
| Fee waivers | Impact, general plan maintenance and street maintenance fees and bedroom taxes waived under 750 sq ft [1] |
| Approval deadline | Completeness answer in 15 business days; decision within 60 days (state law) [2][3] |
| Short-term rental | City program allows some ADU rentals by primary residents, but state law requires 30+ day rentals for state-mandated ADUs and junior ADUs [3][6] |
| Selling an ADU separately | No, except under the state's nonprofit exception [2][3] |
On this page
What you can build in San Rafael
ADUs are allowed in any zoning district that allows single-family or multifamily homes, including commercial districts that allow housing, on a lot with an existing or proposed home. The city's ordinance is San Rafael Municipal Code 14.16.285, last amended in 2022. The city's ADU page says that "where there are conflicts between the most recent state ADU laws and the City's ADU ordinance (last updated in 2022), the state law standards apply."
Single-family lots. The city's ADU page says you can have one detached ADU (new or converted), one attached ADU (new or converted), one junior ADU, or a combination of one detached or attached ADU, one junior ADU and one conversion ADU. The 2022 code text still allows only one ADU per lot in most cases, so this is one of the places where the city says newer state law applies.
Multifamily lots. You can convert non-living space such as basements, laundry rooms or storage areas into ADUs, at least one and up to 25% of the existing units. The city's page and code allow up to two detached ADUs. State law (SB 1211, effective 2025) now allows up to eight detached ADUs on a lot with an existing multifamily building, no more than the number of existing units. Junior ADUs aren't allowed on multifamily lots.
CC&Rs. Homeowners association rules that prohibit or unreasonably restrict ADUs or junior ADUs on single-family lots are void and unenforceable. Statewide rules are on our California page. [1][2][3]
Size, height and setbacks
Size
- Every ADU and junior ADU must be at least 150 sq ft.
- Detached ADU: up to 1,000 sq ft.
- Attached ADU: up to 1,000 sq ft or 50% of the main home, whichever is less, but 800 sq ft is always allowed. The city's examples: a 2,200 sq ft home allows a 1,000 sq ft ADU, an 1,800 sq ft home allows 900 sq ft, and smaller homes allow 800 sq ft.
- Conversions of existing space: no size limit.
- Junior ADU: up to 500 sq ft.
Whatever the lot coverage, floor area ratio, natural state or setback rules say, you are allowed an ADU of up to 800 sq ft with 4-foot side and rear setbacks that meets the height limits.
Height
- Detached: 16 feet; 18 feet within a half-mile walk of a major transit stop or high-quality transit corridor, plus 2 feet to match the main roof pitch; 18 feet on a lot with a multi-story multifamily building.
- Attached: 25 feet or the zone's height limit for the main home, whichever is lower. In the Eichler-Alliance overlay district, attached ADUs are limited to 17 feet (the code says the lower of 17 feet or the existing home's height).
Setbacks. New or expanded ADUs need 4-foot side and rear setbacks. The front setback matches the main home's, unless that would prevent an 800 sq ft ADU. The code also requires the front entry to be 10 feet from any right-of-way, and decks or balconies over 12 inches high to be 4 feet from side and rear lines. Conversions that keep the same footprint need no extra setback. You can tear down an accessory building close to the line and rebuild it as an ADU with the same footprint and dimensions, plus up to 150 sq ft only for entry and exit. [1][2]
Parking
One parking space is required per ADU, unless:
- the ADU is within a half-mile walk of public transit
- it is in an architecturally and historically significant district
- it is created by converting existing space in the house or a detached structure
- on-street parking permits are required but not offered to the ADU's occupant
- a car-share vehicle is within one block when you apply
- it is applied for together with a new single-family or multifamily home on the lot
State law also bars parking requirements for the state-law ADU categories, such as a new detached ADU of up to 800 sq ft with 4-foot side and rear setbacks. The space can be anywhere on the lot, tandem on a driveway, covered or uncovered. Junior ADUs need no parking. If you convert or tear down a garage, carport or covered parking to build an ADU, you don't have to replace it.
The city keeps a map of areas it knows are within a half mile of transit. If you think you qualify but are outside the map, submit a map showing the transit stop and your walking route; staff will check it. [1][2][3]
Fees
Planning fees for an ADU or junior ADU are included in the building permit fees. The planning fee is based on the project's total construction valuation, and electrical, plumbing and mechanical permits are flat-rate fees. For ADUs under 750 sq ft, the city waives impact fees, the general plan maintenance fee, the street maintenance fee and bedroom taxes.
State law separately bars impact fees on any ADU with 750 sq ft or less of interior livable space and requires proportional fees above that. School districts may charge fees only on ADUs over 500 sq ft. For building permit fee questions, email building@cityofsanrafael.org. For typical costs, see our ADU cost guide.
Fire sprinklers can't be required in an ADU if the main home doesn't require them, and an ADU can't trigger sprinklers in the existing home. [1][3]
How long it takes and pre-approved plans
ADUs and junior ADUs that meet the standards are approved ministerially with only a building permit; no discretionary review or public hearing is required. The code says the city acts within 60 days of a complete application when there is already a home on the lot. Under current state law, the city must also tell you within 15 business days whether your application is complete, and if it doesn't approve or deny a complete application within 60 days, it is deemed approved.
Applying. The city accepts only electronic submittals. On February 23, 2026, San Rafael replaced its eTRAKiT system with a new OpenGov online permitting system for new applications; see the Building Division page.
Pre-approved plans. The city has set up a pre-approved ADU plan program for detached ADUs, with an expedited permit process, but says it "does not yet have pre-approved plans." When they exist, they can be used only outside hillside, Wildland Urban Interface, mapped geologic hazard and tsunami inundation areas, still need a parcel-specific site plan, and can't be altered. See our ADU permit guide. [2][3][4][5]
Garage conversions and junior ADUs
Garage conversions. Converting a garage or other existing structure into an ADU has no size limit and needs no new setbacks if the footprint stays the same. It needs no parking, and you don't have to replace the covered parking you lose. An attached converted ADU needs fire-rated separation, egress and separate electrical and mechanical systems under the building code. See our garage conversion guide.
Junior ADUs. One junior ADU is allowed per lot, converted from space inside a single-family home; an attached garage, a primary bedroom or other space in the house can qualify. It must be 150 to 500 sq ft, have its own outside entrance and a kitchen, and it may share bathroom facilities with the house if there is an inside connection. A deed restriction bars selling it separately and limits its size.
Owner occupancy. San Rafael's 2022 code requires the owner to live in the house or the junior ADU. Since January 1, 2026, state law requires owner occupancy only when the junior ADU shares a bathroom with the house, and bars using junior ADUs as short-term rentals. The city says state law applies where they conflict; confirm with the Planning Division. See our junior ADU guide. [1][2][3]
Renting it out, short-term rentals and selling
You can rent out an ADU, and a city can't require you to live on the property to have one. An ADU can't be sold separately from the main home, except under the state's narrow nonprofit exception.
Short-term rentals. The two sets of rules don't line up. The city's short-term rental program says ADUs and junior ADUs may be used as short-term rentals if the host meets its primary residency rules, but you can't rent the whole main home and the accessory unit at the same time. Short-term rentals must register with the city every year and collect transient occupancy tax. But the city's ADU code says ADUs approved under the state-mandated categories can't be rented for less than 30 days, and state law requires those ADUs and all junior ADUs to be rented for more than 30 days. Check with the city before listing an ADU or junior ADU for short stays.
Unpermitted units. The city can't deny a permit to legalize an ADU built before January 1, 2020 just because it violates building or zoning standards, unless fixing a violation is needed to protect health and safety. Legalizing follows the normal building permit process: submit plans, pay permit fees and pass inspections. [1][2][3][6]
Permit steps in San Rafael
Check your lot
Confirm your zoning, front setback, and whether you're in the Eichler-Alliance overlay or within a half mile of transit (the city keeps a transit map). Planning answers questions at (415) 485-3085. [1][7]
Prepare plans
Have plans drawn that meet the building code and the size, height and setback standards; ADUs need kitchen and bathroom facilities and a permanent foundation. [1][2]
Apply for a building permit online
Submit electronically through the city's online permitting system (OpenGov since February 23, 2026), linked from the Building Division page. Planning reviews the ADU within the building permit. [1][4]
Review and decision
The city must say within 15 business days whether the application is complete and act within 60 days of a complete application. [2][3]
Record the junior ADU deed restriction
For a junior ADU, record the deed restriction barring separate sale and limiting size. [2]
Build and pass inspections
Since February 17, 2026, inspections must be scheduled through OpenGov, linked from the Building Division page. The Building Division's inspection line is (415) 485-3365. Pass the final inspection. [1][4]
Pre-approved and sample plans
San Rafael Pre-Approved ADU Plans
An expedited permit path for detached ADUs using pre-approved plans; the city says no plans have been approved yet. [5]
Who to call
-
City of San Rafael Planning Division
ADU zoning questions; community.development@cityofsanrafael.org. Phone hours Monday-Thursday 8 a.m.-4 p.m., Friday 8 a.m.-noon
1400 Fifth Avenue, Top Floor, San Rafael, CA 94901
-
City of San Rafael Building Division
Building permits, plan review and inspections; building@cityofsanrafael.org
1400 Fifth Avenue, Top Floor, San Rafael, CA 94901
Questions people ask
How big can an ADU be in San Rafael?
A new detached ADU can be up to 1,000 sq ft. An attached ADU can be up to 1,000 sq ft or 50% of the main home, whichever is less, with 800 sq ft always allowed. Converting existing space has no size limit, and a junior ADU can be up to 500 sq ft. [1]
How many ADUs can I add to my San Rafael home?
On a single-family lot, one attached or detached ADU, one ADU converted from existing space, and one junior ADU. [1]
Do I need parking for an ADU in San Rafael?
One space per ADU, unless the ADU is within a half-mile walk of public transit, is a conversion of existing space, or meets another state exemption. State law also bars parking requirements for the state-law ADU types, such as a detached ADU of up to 800 sq ft with 4-foot setbacks. Junior ADUs need no parking, and converted garages don't have to be replaced. [1][3]
What fees are waived for small ADUs in San Rafael?
For ADUs under 750 sq ft, the city waives impact fees, the general plan maintenance fee, the street maintenance fee and bedroom taxes. Building permit and plan review fees still apply. [1]
Can I use my San Rafael ADU as a short-term rental?
The city's short-term rental program allows ADUs to be registered by hosts who meet its primary residency rules, but state law requires state-mandated ADUs and all junior ADUs to be rented for more than 30 days. Confirm with the city before listing. [3][6]
Sources (7)
- Accessory Dwelling Units, City of San Rafael. Accessed October 9, 2026.
- San Rafael Municipal Code Section 14.16.285, Accessory dwelling units (ADUs), City of San Rafael. Accessed October 9, 2026.
- Accessory Dwelling Unit Handbook (March 2026), California Department of Housing and Community Development. Accessed October 9, 2026.
- Building Division, City of San Rafael. Accessed October 9, 2026.
- ADU Pre-Approved Plans, City of San Rafael. Accessed October 9, 2026.
- Short-Term Rentals, City of San Rafael. Accessed October 9, 2026.
- Get Help from the Planning Division, City of San Rafael. Accessed October 9, 2026.