What's Required in San Francisco
- A building permit is required for every ADU, with separate electrical, plumbing and mechanical permits for the unit's systems.
- State-program detached ADUs: up to 850 sq ft (studio or one bedroom) or 1,000 sq ft (two or more bedrooms), 18 feet tall plus 2 feet for a matching roof pitch, 4-foot side and rear setbacks.
- No setback is required when an existing structure is converted in place, and a converted ADU may expand up to 150 sq ft for entry access.
- A junior ADU is limited to 500 sq ft inside the house and needs a deed restriction, with owner occupancy only if it shares a bathroom.
- The full permit needs architectural, structural and MEP plans, Title 24 forms, the ADU screening form, the 60-day tolling declaration and Green Building forms; new floor area needs a fire-flow study.
- Local-program ADUs require a Planning Project Application first and a notice posted in the building at least 15 days before filing.
- DBI collects a filing fee before review begins and an issuance fee at approval; Planning charges its building-permit application fee on the same valuation.
- Impact fees are exempt for ADUs under 750 sq ft or on lots with three or fewer units; otherwise they are proportional to the primary home.
- ADUs may not be rented for less than 30 days.
What Does an ADU Permit Cost in San Francisco?
The city's own guide says it plainly: City fees range from 6 to 9 percent of construction costs, and it typically costs at least $125,000 in material and labor to add a unit. Two departments make up most of that. The Department of Building Inspection (DBI) charges plan review plus permit issuance on the project valuation under Table 1A-A, effective July 12, 2026: for work between $50,001 and $200,000, plan review is $1,617 for the first $50,000 plus $15.60 per additional $1,000 and issuance is $677 plus $4.83 per $1,000; from $200,001 to $500,000 the rates are $4,011 plus $13.31 and $1,402 plus $4.21. The Planning Department charges its own building-permit application fee on the same valuation: $5,638 plus 3.855 percent of the cost above $100,000 for work from $100,000 to $499,999. A $125,000 garage conversion therefore pays about $3,826 at DBI ($2,787 plan review plus $1,039 issuance) and about $6,602 at Planning, roughly $10,400 or 8.3 percent. A $300,000 detached cottage pays about $7,165 at DBI and $13,348 at Planning, about $20,500 or 6.8 percent. Trade permits add roughly $1,500 to $2,000: plumbing for a new unit is $549 without underground work or $809 with it, mechanical is $290 for one furnace or heat pump, and electrical is $740 for more than 40 devices. Impact fees are the wild card, and most ADUs avoid them: units under 750 square feet, or on lots with three or fewer existing units, are exempt, and above that they are charged in proportion to the primary home's floor area.
San Francisco ADU Permit Rules by Scenario
| What you are doing | City filing | Rule |
|---|---|---|
| Detached backyard ADU on a single-family lot | State program building permit, Permit Review Roundtable | Up to 850 sq ft (studio or 1 bed) or 1,000 sq ft; 18 ft high; 4-ft setbacks |
| Garage or basement conversion | State program building permit | No size, height or setback limit; 150 sq ft expansion for entry |
| Junior ADU inside the house, up to 500 sq ft | State program building permit + deed restriction | Owner occupancy required only if the JADU shares a bathroom |
| Attached ADU that expands the house | State program building permit | Up to 25 ft high; subjective design review allowed |
| ADU in a 2-to-4-unit building, or needing Planning Code waivers | Local program: Planning Project Application first, then DBI | 15-day tenant notice; likely rent controlled |
| Legalizing an ADU built before 2020 without permits | Building permit under Gov. Code 66332 | Approved unless the unit is substandard |
| Any ADU | Separate electrical, plumbing and mechanical permits | Trade permits filed apart from the building permit |
State Program or Local Program?
San Francisco runs two tracks. The State program (Planning Code 207.2, Government Code 66314 to 66333) is ministerial: Planning's bulletin promises a 60-day review from a complete application, no CEQA, no Section 311 neighborhood notice, no discretionary review and no appeal, and State ADUs are exempt from the local Planning Code except the standards in 207.2. On a single-family lot it allows one detached ADU of up to 850 square feet for a studio or one bedroom or 1,000 square feet for two or more bedrooms, up to 18 feet tall plus 2 feet for a roof pitch matching the house, with 4-foot side and rear setbacks and none at all when you convert an existing structure in place; a converted ADU inside the house has no size cap, and a junior ADU is capped at 500 square feet. State law also bars owner-occupancy requirements. The Local program (207.1) needs in-house Planning review through a Project Application before DBI, can add ADUs to multi-unit buildings, one if the lot has four or fewer units and unlimited if it has five or more, and offers waivers from rear-yard, open-space and exposure rules, but it is barred on lots with owner move-in evictions in the last five years and the new unit will likely be rent controlled.
How the Process Works
Under the State program you file a full permit with DBI: architectural, structural and mechanical-electrical plans plus Title 24 energy forms, the ADU screening form, the 60-day tolling declaration, the Green Building form, a water-fixture count, a Public Health routing checklist and, for new floor area, a fire-flow study; new detached buildings also need an acoustical report. There are two payments, a filing fee that starts review and an issuance fee at approval. Eligible State ADUs are scheduled into a Permit Review Roundtable, a virtual meeting where every reviewing department delivers its comments at once at no extra charge; a second meeting clears your responses. Once approved you pay the remaining fees, receive a job card and pull the trade permits; owners may hold the permit themselves or use a licensed B contractor.
How to Get a ADU Permit in San Francisco
Pick the program
Single-family lots that fit the State standards use the ministerial State program; multi-unit buildings and projects needing Planning Code waivers use the Local program, starting with a Planning Project Application.
Design to the standards
Hire an architect or designer for architectural, structural and MEP plans with Title 24 energy forms; check the size, height and 4-foot setback limits and the fire-flow requirement for new floor area.
Submit the full permit online and pay the filing fee
Upload plans with the ADU screening form, tolling declaration, Green Building form, water-fixture count and Public Health checklist; DBI starts review only after the filing fee is paid.
Attend the Permit Review Roundtable
Eligible State ADUs get one virtual meeting where DBI, Planning, Public Works, Fire and the PUC deliver comments together at no extra fee, and a second to clear responses; the city has 60 days from a complete application.
Pay issuance, get the job card, pull trade permits
Sign the contractor statement or owner package, pay the remaining DBI and Planning fees, then file the separate electrical, plumbing and mechanical permits before inspections begin.