Two numbers, kept apart. City fees come from the city's own fee pages. The build price is our estimate from the last owner survey and today's published prices. How we got it
Official City fees
Line by line
sf.gov says City fees run 6% to 9% of construction cost.See every fee [1]
All in, before school and utility fees: about $350k to $465k for a 750 sq ft detached ADU. Adjust it for your lot
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Building (middle) City fees School fees Parkland
Not included: water and sewer connection, and site surprises like a long utility run or a crane. See the fee list below.
Get 3 quotes to check this numberThe top three by our public score for San Francisco. Some publish prices, which is the quickest check on the estimate above.
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| City fees, all departments (sf.gov rule of thumb) | 6% to 9% of construction cost[1] sf.gov says a new unit typically costs at least $125,000 in material and labor, and architects and engineers add about 10%. |
|---|---|
| Building permit, DBI Table 1A-A (valuation $200,001 to $500,000) | Plan review $4,011 + $13.31 per extra $1,000; issuance $1,402 + $4.21 per extra $1,000[6] For permits issued on or after July 12, 2026. Other departments' fees and trade permits are extra. |
| Permit Review Roundtable (State program) | $0 extra[7] |
| Impact fees | $0 under 750 sq ft or on lots with 3 or fewer units; otherwise in proportion to the main home[8][9] Planning Code Article 4 impact fees were cut 67% from Aug 22, 2026. The inclusionary fee was not cut. |
| School fees (SF Unified) | $3.79 per sq ft[10][1][11] DBI calculates the fee from your application. The city register does not say how ADUs are charged; state law lets districts charge only ADUs over 500 sq ft. |
| Water and sewer capacity charges (SFPUC) | $0 for an ADU on a single-family lot[12][13] SFPUC won't make you upsize your meter. If you choose a new or bigger meter, you pay installation fees only. Buildings with more units pay capacity charges when they add ADUs. |
The last survey of what Bay Area owners actually paid is from UC Berkeley in 2021: a median of $329 per sq ft for ADUs permitted in 2018 and 2019.[2] Construction prices in California have risen about 60% since then by the state's own cost index (2018-2019 average 6,719 to September 2026: 10,717).[3] We check that against two current numbers and use the spread as the range.
Smaller units cost more per foot. We scale by size the way Abodu's own price list does. The survey counted design and permits in its figure, so a little of the city fee may overlap.
Abodu published all-in prices (home + typical installation).[5]
Not included: Survey package ($6,000), trenching past 50 ft, crane past 100 ft, demolition, site engineering and sales tax.
None of these pages cites where its number comes from.
For a 750 sq ft detached ADU, our estimate is $350,000 to $465,000 to build. School and utility fees can add more.[1][2][3][4]
The city doesn't publish a total. No published total. sf.gov says City fees run 6% to 9% of construction cost. The fee lines on this page list each charge.[1]
No. State law bars impact fees on ADUs under 750 sq ft. Larger ADUs pay in proportion to the main home. School fees follow a different rule, and districts disagree about it, so ask yours.[11]
Every fact on this page links to one of these. We read each one on the date shown.