ADU Rules in San Francisco, CA (2026)
ADU rules, permit requirements, size limits, and fees for San Francisco, CA. Source-cited from official municipal code.
Yes, ADUs are allowed in San Francisco, CA.
San Francisco, CA permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. California state law actively preempts local restrictions, making ADU approval a streamlined ministerial process. In San Francisco, the San Francisco Department of Building Inspection (DBI) handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in San Francisco.
ADU Size Limits
ADU Size Limits in San Francisco: Detached ADU: up to 1200 sq ft (max height: 16 feet). Attached ADU: 50% of primary dwelling up to 1200 sqft. Junior ADU (JADU): up to 500 sq ft — must be within the existing primary dwelling or accessory structure. Detached ADU maximum 1,200 sqft per California Gov Code 65852.2(c)(2)(B). JADU must be within existing or proposed space of primary structure or accessory structure. Garage conversion ADUs limited to existing footprint plus 150 sqft for ingress/egress. SF Planning Code Section 207.1 governs locally.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | 1200 sq ft | 16 feet |
| Attached ADU | 50% of primary dwelling up to 1200 sqft | Same as primary dwelling height limit per zone |
| JADU | 500 sq ft | Within existing structure |
Permit Fees
ADU Permit Fees in San Francisco: Plan check fee: Varies — typically $800–$3,500 for standard ADU based on project valuation. Building permit fee: Varies by valuation — typically $2,000–$6,000. Impact fees: None. School fees: Exempt for ADUs under 750 sqft per Gov Code 65852.2(f)(3). ADUs 750+ sqft subject to school developer fees.. Total estimated permit cost: $3,000–$10,000 total permit fees depending on size and scope. Impact fees waived for ADUs under 750 sqft per Gov Code 65852.2(f)(3). Fee schedule: https://sfdbi.org/permits/permit-fees. SF DBI permit fee calculator available online.
| Fee Type | Amount |
|---|---|
| Plan Check | Varies — typically $800–$3,500 for standard ADU based on project valuation |
| Building Permit | Varies by valuation — typically $2,000–$6,000 |
| Impact Fees | None |
| School Fees | Exempt for ADUs under 750 sqft per Gov Code 65852.2(f)(3). ADUs 750+ sqft subject to school developer fees. |
| Total Estimate | $3,000–$10,000 total permit fees depending on size and scope |
Permit Timeline
San Francisco ADU Permit Timeline: Ministerial approval required within 60 days per Gov Code 65852.2(a)(3). SF DBI (Department of Building Inspection) ADU permits typically processed in 2-6 weeks for plan check. SF Planning pre-approval may add time if design review triggered. Apply through the San Francisco Department of Building Inspection (DBI) online permit portal. Phone: (415) 558-6088.
Setback Requirements
ADU Setback Requirements in San Francisco: Front setback: Same as zone standard. Side setback: 4 feet. Rear setback: 4 feet. State law requires 4-foot side and rear setbacks for new detached ADUs per Gov Code 65852.2(c)(2)(E). No setback required for ADU replacing existing structure in same footprint. Front setback follows Planning Code zone standards. SF Planning Code Section 207.1.
Parking Requirements
Parking Requirements: No additional parking required for ADUs within one-half mile of public transit (BART, Muni Metro, major bus lines). SF is entirely transit-rich — parking waivers apply throughout the city per California Gov Code 65852.2(d)(1)(A) and SF Planning Code Section 207.1.
Restrictions & Requirements
- ADU must comply with objective Planning Code standards
- ADU cannot be sold separately from primary dwelling (except under SB 9 lot split)
- Short-term rental of ADU requires primary resident to be on-site during rental
- ADU must have permanent foundation
- In-law units in RH-1 zones must meet residential habitability standards
- Hillside areas may have additional structural review requirements
How Many ADUs Are Allowed?
Number of ADUs Allowed in San Francisco: Single-family lots: 1 ADU + 1 JADU per single-family lot (RH-1, RH-2 zones). Multifamily properties: Up to 25% of existing units (minimum 2) as detached ADUs; 1 ADU per existing unit for internal conversions per Gov Code 65852.2(e). Per Gov Code 65852.2(e)(1)(B): multifamily properties may convert up to 25% of existing units to ADUs. SB 9 Urban Lot Split may allow additional units on qualifying RH-1 parcels.
Single-Family Lots
1 ADU + 1 JADU per single-family lot (RH-1, RH-2 zones)
Multifamily Properties
Up to 25% of existing units (minimum 2) as detached ADUs; 1 ADU per existing unit for internal conversions per Gov Code 65852.2(e)
State Law & Preemption
State Preemption: California Government Code Section 65852.2 (as amended by AB 68 2019, AB 881 2019, SB 9 2022) preempts local ADU restrictions. San Francisco must permit ADUs by-right on all single-family and multifamily residential lots. Owner-occupancy requirement eliminated statewide as of January 1, 2020. SF had some of the most restrictive local ADU rules before state law superseded them.
Historic District Considerations
Historic District Requirements: San Francisco has 11 historic districts where additional design review may be required for ADU construction. Design review approval is required before obtaining a building permit for properties in historic overlay zones. San Francisco has 11 Article 10 Landmark Designations and numerous Article 11 Significant Buildings (800+ individually designated). Historic districts include: Alamo Square, Civic Center, Jackson Square, Liberty Hill, Noe Valley, North Beach, Pacific Heights, Potrero Hill, South Park, Tenderloin, Western Addition. Article 10 Landmarks require Certificate of Appropriateness for exterior changes. Article 11 buildings require Planning Department review. Look up historic district boundaries at: https://sfplanning.org/resource/historic-preservation
Frequently Asked Questions
Can I build an ADU in San Francisco?
Yes. San Francisco, CA allows accessory dwelling units. On a single-family lot you can build 1 ADU + 1 JADU per single-family lot (RH-1, RH-2 zones).
How big can an ADU be in San Francisco?
The maximum size for a detached ADU in San Francisco is 1,200 square feet. A Junior ADU (JADU) can be up to 500 square feet.
How long does it take to get an ADU permit in San Francisco?
The typical ADU permit timeline in San Francisco is Ministerial approval required within 60 days per Gov Code 65852.2(a)(3). SF DBI (Department of Building Inspection) ADU permits typically processed in 2-6 weeks for plan check. SF Planning pre-approval may add time if design review triggered.. Total estimated permit fees are $3,000–$10,000 total permit fees depending on size and scope.
Do I need extra parking for an ADU in San Francisco?
No, San Francisco does not require additional parking for ADUs.
Do I have to live on-site to have an ADU in San Francisco?
No, owner-occupancy is not required for ADUs in San Francisco.
Source: San Francisco Planning Code Section 207.1; California Government Code Section 65852.2. Last verified April 5, 2026. View source