San Francisco ADUs: 60-day permit decision, all-in ADUs from $124,900
San Francisco rents jumped 25% in a year, yet fewer ADUs are being permitted than in 2022. Under the State ADU program a backyard cottage is approved ministerially in 60 days. We deliver it all-in from our factory in Lathrop — permits, foundation, delivery and installation included — at one fixed price.
Free lot check · zoning, historic status, access · reply with a fixed price
Licensed builder · Our own factory in Lathrop, CA
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Quick answer
Yes, you can build: up to 1,000 sq ft, 60-day decision, no neighbor appeals
Most San Francisco homeowners with a backyard can add a detached ADU under the State program: up to 850–1,000 sq ft, approved in 60 days with no neighbor appeals, no impact fees under 750 sq ft — and Bay Modular delivers it all-in for $124,900–$271,900, the same price anywhere in California.
- Can I build a backyard ADU in San Francisco?
- Yes. Under the State ADU program, a single-family lot can add one detached ADU up to 850 sq ft (1,000 sq ft with 2+ bedrooms), 18 ft tall, 4 ft from side and rear lines.
- How long does an SF ADU permit take?
- State-program ADUs are reviewed ministerially within 60 days of a complete application — no neighbor notice, discretionary review or appeal.
- What fees does San Francisco charge?
- No impact fees under 750 sq ft. The SFUSD school fee ($3.79 per sq ft) applies only to ADUs over 500 sq ft.
- How much does a prefab ADU cost in San Francisco?
- Bay Modular: $124,900–$271,900 all-in, the same price as anywhere in California, permits and installation included.
- Is a new SF ADU under rent control?
- Units built after June 1979 are exempt from SF rent-increase limits, but SF just-cause eviction rules apply. Local-program ADUs can be rent-controlled.
- What does an ADU rent for in San Francisco?
- Average asking rent in San Francisco was $4,682 a month in August 2026 (Zillow), up 25% in a year.
Sources: SF Planning ADU page and Director Bulletin No. 3 (June 2026), SF Rent Board, HCD APR 2025, Zillow ZORI Aug 2026. Last reviewed October 2026.
San Francisco in numbers
SF rents rose 25% in a year — while ADU permits fell by half
San Francisco permitted half as many ADUs in 2025 as in 2022 — while rents rose faster than anywhere else in our coverage.
ADU permits issued in the City of San Francisco
Source: California HCD Annual Progress Report data (Table A2), City of San Francisco, permits issued per year. Percent = ADUs among all housing units permitted in the city that year.
average San Francisco asking rent since January 2021 ($2,895 → $4,682)
Zillow Observed Rent Index, City of San Francisco, Aug 2026rent growth in just one year (Aug 2025 $3,739 → Aug 2026 $4,682)
Zillow Observed Rent Index, City of San FranciscoWhere San Francisco homeowners add ADUs
ADU permits issued on existing single-family and two-unit homes since 2013, by neighborhood — most are conversions. For new-construction ADUs the leaders are Oceanview/Merced/Ingleside, Sunset/Parkside, Bayview, Bernal Heights and West of Twin Peaks. Source: DataSF Building Permits (data as of March 2026).
Can I build in San Francisco?
Most SF backyards qualify — no rear-yard rules, no neighbor appeals
San Francisco offers two ADU programs; for backyard cottages the State program is usually simplest. Here is what matters for most homeowners:
Up to 850 sq ft for a studio or 1-bedroom, 1,000 sq ft with 2+ bedrooms. All our models fit.
4 ft from side and rear lot lines; up to 18 ft tall, plus 2 ft to match the house roof.
State-program ADUs don't need to meet SF's rear-yard or exposure rules — the biggest local hurdle is gone.
One detached ADU plus one converted ADU and one JADU on a single-family lot.
Ministerial review: no neighbor notice, no discretionary review and no appeal for State ADUs.
On listed historic properties the ADU must meet standards that protect the historic resource. We check first.
Based on SF Planning’s ADU page and Planning Director Bulletin No. 3 (updated June 2026, Gov. Code §66323). Not legal advice — rules depend on your exact lot. More in our San Francisco ADU guide.
New in 2027: under AB 956 (Chapter 791, Statutes of 2026), from January 1, 2027 state law lets you build two detached ADUs on a lot with a single-family home, and HOA rules can’t block an ADU on a lot zoned to allow one.
Costs & fees in San Francisco
One fixed price — ADUs from $124,900 — $0 city impact fees under 750 sq ft
Same all-in price as anywhere in California. Our models are all under 750 sq ft, so none pays San Francisco impact fees — and four of five pay no school fee.
| Model | All-in price | School fees | City impact fees |
|---|---|---|---|
| Backyard Studio120 sq ft · home office or guest studio, not a rentable ADU | $75,900 | $0 | $0 |
| Small Studio256 sq ft | $124,900 | $0 | $0 |
| Large Studio ADU320 sq ft | $154,900 | $0 | $0 |
| 1 Bedroom ADU480 sq ft | $214,900 | $0 | $0 |
| 2 Bedroom ADU640 sq ft | $271,900 | $2,426 | $0 |
Sources: SF Planning Director Bulletin No. 3 (June 2026); SF Impact Fee Register (Jan 2026, SFUSD $3.79/sq ft); sf.gov “Get a building permit for an ADU” (Oct 2026); Gov. Code §66311.5. Launch pricing runs through December 31, 2026. Comparison is general — every project differs.
Renting in San Francisco
Rent averages $4,682/mo — no SF rent-increase limits on new ADUs
$4,682/moaverage asking rent for all homes in San Francisco — up 25% in one year and 62% since 2021.
Zillow Observed Rent Index, City of San Francisco, Aug 2026 ADU for rental incomeSF ADUs can't join the short-term rental program; every rental must be longer than 30 days.
Units built after June 1979 are exempt from SF rent-increase limits, but SF just-cause eviction rules apply. Local-program ADUs can be rent-controlled — we use the State program where possible.
Since 2025, SF lets a State detached ADU next to a single-family home become a condo and be sold on its own (Ord. 113-25).
Same money, other options
Yearly income per dollar, before taxes and costs. An ADU wins because you already own the land. Full comparison →
Sources: SF Planning ADU page and Bulletin No. 3; SF Rent Board “Partial exemption for newly constructed units”; SF Ordinance 113-25. Comparison: HUD FY2027 2-bedroom Fair Market Rent, San Francisco area ($3,697) × 12 ÷ $271,900; U.S. Treasury (Oct 6, 2026); FTSE Nareit (Sep 2026); Zillow ZORI ÷ ZHVI, San Francisco metro (Aug 2026); FDIC (Sep 2026). Not legal or investment advice.
Permits in San Francisco
We handle your SF permit — the City must decide within 60 days
Free lot check
Zoning, historic status, lot lines, sewer and power for your San Francisco address.
Plans & submittal
Our HCD-approved plans plus your site plan, filed under the State ADU program with DBI and Planning.
Ministerial review
No neighbor notice, no discretionary review, no appeals. We answer city comments for you.
Decision in 60 days
The City must act on a complete State-program application within 60 days. Your ADU is built in our factory meanwhile.
Install & move in
Delivered from our Lathrop factory, installed in about a week, inspected, then your Certificate of Occupancy.
Based on SF Planning Director Bulletin No. 3 (June 2026) and the SF Planning ADU page (Oct 2026). Narrow lot with no side access? We confirm how the ADU gets to your backyard during the free lot check.
Why now
Save up to $81,000 — free lot check and a fixed quote before you commit
Lock in launch pricing, see exactly what you get, and only decide once you have a fixed price for your lot.
All-in from $75,900 — everything included
- Backyard Studio (home office)$75,900All-in · fixed in writing
- Small Studio$124,900All-in · fixed in writing
- Large Studio ADU$154,900All-in · fixed in writing
- 1 Bedroom ADU$214,900All-in · fixed in writing
- 2 Bedroom ADU$271,900All-in · fixed in writing
Zero-risk start
- Free lot check & quoteNo obligation, no credit card.
- One fixed all-in priceDesign, permits, delivery and install — one number.
- HCD-approved plansState approval #1585366, financed and appraised like a home.
- 2-year warrantyOn materials and workmanship.
Visit our factory in Lathrop, CA and walk through a finished ADU.
San Francisco ADU questions, answered
Read the full San Francisco ADU guide, see all of California, or call (209) 214-6845.
Can I build an ADU in my backyard in San Francisco?
Usually yes. Under the State ADU program a single-family lot can add one detached ADU up to 850 sq ft (1,000 sq ft with 2+ bedrooms), 18 ft tall, with 4-foot side and rear setbacks — and SF's rear-yard rules don't apply. We check your address for free.
How much does an ADU cost in San Francisco?
Our all-in prices are the same as anywhere in California: from $124,900 for a Small Studio to $271,900 for a 2 Bedroom ADU, with launch pricing through December 31, 2026. There are no impact fees under 750 sq ft, and the SFUSD school fee applies only above 500 sq ft.
How long does an ADU permit take in San Francisco?
State-program ADUs are reviewed ministerially, with a decision required within 60 days of a complete application and no neighbor appeals. Your ADU is built in our factory at the same time, so most projects take 4–6 months from signing to keys.
Is a new ADU in San Francisco under rent control?
Units first built after June 13, 1979 are exempt from SF's rent-increase limits, but SF just-cause eviction rules apply. ADUs built under SF's Local program can be subject to rent control, so we use the State program where possible.
Can I rent my SF ADU on Airbnb?
No. ADUs are ineligible for San Francisco's short-term rental program; rentals must be longer than 30 days.
Can I sell my ADU separately in San Francisco?
Yes, in many cases. Since 2025 SF allows a State detached ADU next to a single-family home to be converted to a condo and sold (Ordinance 113-25), if the lot has four or fewer units.
Do neighbors get a say?
Not under the State program: there is no neighbor notification, discretionary review or appeal for State ADUs.
Is an ADU a better investment than a rental property in San Francisco?
For most homeowners with a backyard, yes: you don't buy land. A 2 Bedroom ADU at HUD's 2027 fair rent for a 2-bedroom ($3,697) earns about 16.4% a year on its price before costs, vs. about 3.6% for a typical SF-area rental home (Zillow, Aug 2026). Not investment advice.
Free · no obligation
Find out free if your San Francisco lot qualifies
Send your San Francisco address. We'll check zoning, historic status, access and utilities, and send a fixed all-in price — permits included.
HCD-approved plans (#1585366) · 2-year warranty · factory in Lathrop, CA
Sources: California HCD Annual Progress Report data, Table A2 (San Francisco, 2021–2025, updated Oct 2026); Zillow Observed Rent Index, City of San Francisco (Aug 2026); SF Planning ADU page and Planning Director Bulletin No. 3 (June 2026); SF Impact Fee Register (Jan 2026); SF Rent Board; SF Ordinance 113-25; Gov. Code §66311.5, §66323; HCD ADU Handbook (2026). General information, not legal or investment advice. Updated October 2026.