San Francisco has embraced ADUs as a key housing solution, with one of the most progressive ADU programs in the state. The city offers expedited review, fee waivers, and pre-approved plans to encourage ADU development.
San Francisco ADU Overview
San Francisco is one of California's most active ADU markets. The city has issued thousands of ADU permits since streamlining its approval process, with the average San Francisco ADU taking 4-8 months from application to completion. SF's high rents ($2,200-$3,500/month for a 1-bedroom ADU) make the investment math compelling despite higher construction costs. Both attached and detached ADUs are allowed in all residential zones, and the city offers pre-approved ADU plans to speed up permitting. Garage conversions are particularly popular in neighborhoods like the Sunset, Richmond, and Excelsior where two-car garages are common.
New in 2026: Two important state laws took effect January 1, 2026. SB 543 strengthens the deemed-approved provision — if San Francisco fails to act on your ADU application within 60 days, it is automatically approved. If the city fails to bring a non-compliant local ADU ordinance into line after an HCD finding, that ordinance can be rendered null and void so state standards apply. AB 1154 removed JADU owner-occupancy only where the JADU has its own separate bathroom; a JADU that shares sanitation facilities with the main home still requires the owner to live on-site. These changes apply on top of existing protections like AB 976 (no owner-occupancy for detached ADUs) and SB 1211 (up to 8 detached ADUs on multifamily lots).
Zoning & Size Requirements [1][2]
Yes — San Francisco allows ADUs. A detached ADU can typically be up to 850 sq ft under current California and San Francisco zoning rules.
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| Allowed Zones | MORE GENEROUS than our list. ADUs are allowed on ANY lot in a zoning district that allows residential use — including mixed-use and commercial districts, not just the RH/RM/RTO family. PC 207.1(b) applies the Local Program to 'all lots located within the City and County of San Francisco in areas that allow residential use'. One SF-specific exclusion worth stating: PC 207.1(c)(12) bars an ADU in a Neighborhood Commercial District or the Chinatown Community Business or Visitor Retail Districts if it would eliminate or reduce ground-story retail space, unless it is a Designated Child Care Unit. |
| Max Size (Detached) | 850 sq ft gross floor area for a detached ADU with one bedroom or less; 1,000 sq ft for two or more bedrooms. Same cap in BOTH programs (State: PC 207.2(c)(1) and (d)(5)(B); Local: PC 207.1(c)(15)(B)). Exception: a detached ADU on a lot with an existing multifamily building under the State Program has NO maximum size. NOTE: SF measures this as GROSS FLOOR AREA, not interior livable space. |
| Max Size (Attached) | MORE GENEROUS THAN OUR PAGE SAYS. State Program (PC 207.2(d)(5)(A)): an attached ADU with one bedroom or less may be 50% of the gross floor area of the existing primary dwelling OR 850 sq ft, WHICHEVER IS GREATER; two or more bedrooms, 50% OR 1,000 sq ft, whichever is greater. Our wording implies whichever is lesser. On a 3,000 sq ft house a two-bedroom attached ADU may be 1,500 sq ft. Local Program (PC 207.1): attached and converted ADUs have NO maximum size at all. An attached ADU may NOT be combined with any other ADU type. |
| Max Size (JADU) | 500 sq ft of interior livable space — correct, adopts the state definition. Add the SF-specific caveat: a JADU exists ONLY in the State Program (single-family buildings). The Local Program offers no JADU. A JADU may be combined with a Detached ADU and a Converted ADU. |
| Max Height | MORE GENEROUS. State Program (PC 207.2(d)(9)): detached ADU up to 18 FEET on any lot with an existing or proposed dwelling, plus 2 additional feet to accommodate a roof pitch aligned with the primary dwelling (20 ft total); attached ADU up to 25 feet. SF grants the 18 ft with NO transit-proximity or multistory-multifamily condition. Local Program (PC 207.1(c)(15)(A)): detached rear-yard ADU limited to 16 feet; converted ADUs have no height limit; otherwise height follows the zoning district and no vertical addition is allowed except in the limited cases in 207.1(c). |
| Max Units | SUBSTANTIALLY MORE GENEROUS — this is the headline correction. STATE PROGRAM, single-family lot: 1 Detached + 1 Converted + 1 JADU, all combinable = up to 3 new units (an Attached ADU is 1 and may NOT be combined with others). STATE PROGRAM, multifamily: up to 8 detached ADUs on a lot with an existing MF building, not exceeding the number of existing units (2 detached on a proposed MF building), plus converted ADUs equal to 1 or up to 25% of existing units. LOCAL PROGRAM, existing buildings: 4 or fewer legal dwelling units on the lot = 1 ADU + 1 Detached ADU; 5 or more legal units = UNLIMITED ADUs + 1 Detached ADU; any property undergoing mandatory (Building Code Ch. 4D) or voluntary (AB-094) seismic upgrade = UNLIMITED ADUs + 1 Detached ADU. LOCAL PROGRAM, new construction: zoning allows 4 or fewer units = 1 + 1 detached; 5 or more = unlimited + 1 detached. The State and Local programs CANNOT be combined. |
Setback Requirements [1][2]
San Francisco requires a rear setback of about 4 ft for a detached ADU, and no additional parking is required. Owner-occupancy is set by local rules (confirm with the city).
| Rear Setback | 4 ft is right for a NEW detached structure, but wrong as a blanket rule. State Program (PC 207.2(d)(7)): NO setback is required for an ADU within an existing living area or existing accessory structure, or one that replaces an existing structure at the same location and dimensions; a setback of no more than 4 ft applies otherwise; and for new construction the 4 ft applies only to portions outside the buildable area. Local Program: 4 ft for the detached rear-yard ADU (207.1(c)(15)(A)); but converted space needs NO setback and other Local-Program ADUs must meet the underlying zoning district rear yard (in SF RH districts typically 25% of lot depth, far more than 4 ft) unless the Zoning Administrator grants a rear-yard waiver under 207.1(g). |
| Side Setback | Same treatment as rear: 4 ft from side lot lines for a new detached ADU under both programs; zero for conversions and same-footprint replacements; and under the State Program the 4 ft applies to new construction only for portions outside the buildable area. Local-Program non-detached ADUs follow the zoning district. |
| Front Setback | Broadly right, but incomplete. Under the State Program PC 207.2(d) bars the City from applying lot coverage, FAR, open space, FRONT SETBACK or minimum lot size rules in a way that would prevent an ADU of 800 sq ft or less, 16 ft or less, with 4 ft side and rear setbacks. So the zone's front setback applies but cannot be used to block a conforming small ADU. Under the Local Program the front setback applies per the zoning district and is NOT among the waivers available under PC 207.1(g) (which cover density, bicycle parking, rear yard, exposure and open space only). |
| Parking Required | Value stands, but add the SF-specific trap. Neither PC 207.1 nor PC 207.2 imposes any parking requirement on an ADU, and PC 207.2(d)(8) expressly bars requiring replacement spaces when a garage, carport or covered parking structure is demolished or converted for an ADU. HOWEVER: under the Local Program an ADU may not sever a tenant's 'housing service' — which SF Planning states includes a garage, laundry room and storage — without just cause, and PC 207.1(c)(13) bars removing on-site laundry unless replaced with equal number/capacity. So there is no parking minimum, but taking an existing tenant's garage can block the project. |
| Owner Occupancy | Correct for ADUs — neither PC 207.1 nor PC 207.2 imposes owner occupancy, matching Gov. Code 66315. Add the JADU exception SF actually applies: if a JADU SHARES sanitation facilities with the main residence, the owner must record a deed restriction that includes an owner-occupancy requirement in either the JADU or the primary home. A JADU with its own bathroom carries no owner-occupancy requirement. |
| Min Lot Size | No minimum lot size — correct, SF adopts the state floor. PC 207.2(d) expressly forbids the City from imposing a minimum lot size that would prevent an 800 sq ft / 16 ft / 4 ft-setback ADU, and PC 207.1 imposes no lot-size minimum. Eligibility instead turns on the lot being in a district that allows residential use and containing an existing or proposed dwelling. |
Permit Process & Fees [3]
An ADU permit in San Francisco goes through a ministerial, by-right review. Typical timeline: 60 days from a COMPLETE application under Gov. Code 66317 — but SF requires every ADU applicant to sign an 'Application Processing Time Tolling Declaration Form' electing either to TOLL (pause) the 60-day clock while revising plans, or to hold the City to it. If the applicant declines tolling, DBI may DENY the application if code compliance cannot be established within 60 days, and revised plans must be resubmitted at least 10 business days before the period ends. Most applicants therefore toll and the real elapsed time exceeds 60 days. Add the Local-Program pre-clock: 15 calendar days of posted notice before filing, a Rent Board declaration with a 30-day tenant petition window (Rent Board targets transmitting a determination within 90 calendar days of a petition), then Planning In-House Review and a Planning Approval Letter — all before the building permit is filed. SF states State-Program full permits 'generally has a shorter review and issuance timeline than the Local program.'. Permit fees: Replace the guessed range with SF's own published figures. DBI's own estimate: 'City fees range from 6-9% of construction costs' (and architects/engineers about 10%; at least $125,000 in material and labor for a new unit). PLANNING development application fee (Fee Schedule eff. 8/29/2025, rev. 6/15/2026) — New Construction: $3,502 flat under $100k; $3,504 base + 3.855% of cost above $100,000 in the $100k-499,999 band; $19,226 + 1.230% above $500,000. Alteration/Change of Use (garage or interior conversion): $504 under $10k; $516 + 5.274% above $10,000; $3,838 + 3.524% above $50,000; $5,638 + 3.855% above $100,000. Neighborhood notification $121 + $4.25/envelope; permit-revision back check $366. DBI building permit fees are TWO separate charges under SF Building Code Table 1A-A (amended Ord. 112-26, eff. 7/12/2026) — Plan Review: $1,671 + $15.60 per $1,000 over $50,000 ($50k-200k band), $4,011 + $13.31 per $1,000 over $200,000 ($200k-500k band); Permit Issuance: $677 + $4.83 per $1,000 ($50k-200k), $1,402 + $4.21 per $1,000 ($200k-500k). Table 1A-A note 1 states these exclude Public Works, Planning, Fire, Public Health and plumbing/electrical/mechanical permit fees. Add SFUSD school facility fees (calculated by DBI staff), SFPUC and Public Works right-of-way permits. OUR WORKED EXAMPLE (label as our calculation, not a published number): a $300,000 detached ADU = Planning $11,214 + DBI plan review $5,342 + DBI issuance $1,823, roughly $18,400 before trade permits and school fees — about 6% of construction cost, consistent with DBI's 6-9%. FEE WAIVER: building permit fees are waived for permits granting legal status to dwelling units built without permits, for activities prior to 1/1/2020 (Board Ord. 150571).
| Approval Process | TRUE ONLY OF THE STATE PROGRAM — must be split. STATE PROGRAM: ministerial; no CEQA; no Planning Code Sec. 311 neighborhood notification; no discretionary review; no subjective design review except historic-resource standards for ADUs under Gov. Code 66314; appeals prohibited under AB 1114 for permits filed on or after 1/1/2024; eligible for a free virtual Permit Review Roundtable with DBI, Planning, Public Works, SF Fire and SFPUC in one meeting. LOCAL PROGRAM: requires (a) a Notice of Addition of ADU plus declaration posted in the building and mailed/delivered to every unit including unauthorized units at least 15 CALENDAR DAYS before applying; (b) a declaration filed with the Rent Board under penalty of perjury regarding severance of housing services, which tenants may contest by petition within 30 calendar days; (c) a Project Application (PRJ) to Planning for In-House Review and a Planning Approval Letter BEFORE DBI will accept the building permit; (d) possible Historic Resource Review; (e) Zoning Administrator waivers under PC 207.1(g)/307(l); (f) a recorded Regulatory Agreement / Costa-Hawkins agreement where waivers are granted on a lot with Rental Units. BOTH: an ADU Screening Form must be filed with the permit application, on which the applicant elects State/Hybrid or Local and signs a Rent Ordinance affidavit. ELIGIBILITY BAR (Local only): no ADU where there was an owner move-in eviction within 5 years or another no-fault eviction within 10 years. |
| Review Timeline | 60 days from a COMPLETE application under Gov. Code 66317 — but SF requires every ADU applicant to sign an 'Application Processing Time Tolling Declaration Form' electing either to TOLL (pause) the 60-day clock while revising plans, or to hold the City to it. If the applicant declines tolling, DBI may DENY the application if code compliance cannot be established within 60 days, and revised plans must be resubmitted at least 10 business days before the period ends. Most applicants therefore toll and the real elapsed time exceeds 60 days. Add the Local-Program pre-clock: 15 calendar days of posted notice before filing, a Rent Board declaration with a 30-day tenant petition window (Rent Board targets transmitting a determination within 90 calendar days of a petition), then Planning In-House Review and a Planning Approval Letter — all before the building permit is filed. SF states State-Program full permits 'generally has a shorter review and issuance timeline than the Local program.' |
| Permit Fees | Replace the guessed range with SF's own published figures. DBI's own estimate: 'City fees range from 6-9% of construction costs' (and architects/engineers about 10%; at least $125,000 in material and labor for a new unit). PLANNING development application fee (Fee Schedule eff. 8/29/2025, rev. 6/15/2026) — New Construction: $3,502 flat under $100k; $3,504 base + 3.855% of cost above $100,000 in the $100k-499,999 band; $19,226 + 1.230% above $500,000. Alteration/Change of Use (garage or interior conversion): $504 under $10k; $516 + 5.274% above $10,000; $3,838 + 3.524% above $50,000; $5,638 + 3.855% above $100,000. Neighborhood notification $121 + $4.25/envelope; permit-revision back check $366. DBI building permit fees are TWO separate charges under SF Building Code Table 1A-A (amended Ord. 112-26, eff. 7/12/2026) — Plan Review: $1,671 + $15.60 per $1,000 over $50,000 ($50k-200k band), $4,011 + $13.31 per $1,000 over $200,000 ($200k-500k band); Permit Issuance: $677 + $4.83 per $1,000 ($50k-200k), $1,402 + $4.21 per $1,000 ($200k-500k). Table 1A-A note 1 states these exclude Public Works, Planning, Fire, Public Health and plumbing/electrical/mechanical permit fees. Add SFUSD school facility fees (calculated by DBI staff), SFPUC and Public Works right-of-way permits. OUR WORKED EXAMPLE (label as our calculation, not a published number): a $300,000 detached ADU = Planning $11,214 + DBI plan review $5,342 + DBI issuance $1,823, roughly $18,400 before trade permits and school fees — about 6% of construction cost, consistent with DBI's 6-9%. FEE WAIVER: building permit fees are waived for permits granting legal status to dwelling units built without permits, for activities prior to 1/1/2020 (Board Ord. 150571). |
| Impact Fees | MORE GENEROUS THAN STATE LAW — commercially the second-biggest correction. PC 207.2(j) waives impact fees for a State-Program ADU or JADU that is under 750 sq ft of Gross Floor Area, OR that is proposed on a lot with THREE EXISTING UNITS OR FEWER regardless of size. So on a typical SF single-family, duplex or triplex lot, a State-Program ADU pays NO impact fees even at 1,000 sq ft. Above those thresholds, fees are imposed proportionately to the gross floor area of the primary dwelling unit. CAVEAT TO FLAG: the Planning Code says 'Gross Floor Area' for the 750 threshold while Planning Director Bulletin No. 3 says 'interior livable space' — the code controls. SECOND CAVEAT: 207.2(j) is expressly limited to the State Program; PC 207.1 contains no parallel exemption, so Local-Program impact fees are unresolved. |
| Plan Check | Expedited plan check available |
| Pre-Approved Plans | MISLEADING AS WRITTEN — rewrite. DBI runs a Pre-approved ADU Plans program, but it is a program for BUILDING DESIGNERS to submit designs for pre-approval, not a homeowner catalogue. Verified terms: a $2,408 flat fee per plan submitted for pre-approval (a widely repeated $1,519 figure is stale); plans 'should be designed for 25 ft lots'; pre-approval 'is only valid during the current code cycle'; pre-approved plans CANNOT be used in slope protection areas, landslide and liquefaction zones, Maher Zones or flood zones; and site-specific plan check is still required (Planning Code compliance, soils report and site survey, fire separation distance, foundation design, SFUSD fees, tree removal, drainage). Submissions go to dbi.preapprequests@sfgov.org and DBI schedules a Permit Review Roundtable. Do NOT claim it 'saves 2-3 months on design' — nothing on the city's pages supports a time saving. I found NO published catalogue of pre-approved plans; SF Planning's ADU page, Planning Director Bulletin No. 3 and the Local ADU Program Chart do not mention the program at all. |
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Construction Costs [4][5]
Building an ADU in San Francisco typically costs $200,000-$450,000 ($300-$500 per sq ft); a garage conversion runs $120,000-$250,000.
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| Average Build Cost | $200,000-$450,000 |
| Cost per Sq Ft | $300-$500 |
| Garage Conversion | $120,000-$250,000 |
| Prefab ADU (Installed) | $150,000-$350,000 |
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Rental Income Potential [6][7]
A 2-bedroom ADU in San Francisco rents for around $2,800-$4,000/mo, an estimated 5-8% annual return.
| Avg Rent (1 Bedroom) | $2,200-$3,200/mo |
| Avg Rent (2 Bedroom) | $2,800-$4,000/mo |
| Short-Term Rental | Not allowed — SF ADUs and JADUs are ineligible for the Short-Term Rental program; minimum 30-day rentals only |
| Est. Annual ROI | 5-8% annual return |
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Recent Law Changes
What's Changed Recently
- Data accuracy correction (2026-06-28): updated per official city/state sources following a regulatory audit.
- SB 543 (effective Jan 1, 2026): ADU applications deemed approved if city fails to act within 60 days; HCD can nullify non-compliant local denials
- AB 1154 (effective Jan 1, 2026): A locality may require owner-occupancy for a JADU only if it shares a bathroom with the primary dwelling; JADUs with their own bathroom are exempt (matching detached ADU rules)
- SB 1211 in effect: Up to 8 detached ADUs allowed on multifamily lots statewide
- AB 1033 opt-in expanding: More cities allowing separate sale of ADUs as condos
- SF's Dwelling Unit Legalization Program (a permanent program, not a time-limited amnesty) can legalize unpermitted units built before Jan 1, 2013
- The CalHFA $40,000 ADU Grant is closed — funds were exhausted in December 2023 and no new round is open as of 2026; CalHFA warns that anyone claiming they can still secure it is running a scam
Tips for Building an ADU in San Francisco
- SF now offers pre-approved ADU plans — check sfplanning.org for standard plan sets that can save 2-3 months on design
- SB 543 deemed-approved provision means if SF does not act on your ADU application within 60 days, it is automatically approved. Track your deadlines carefully.
- AB 1154 (effective Jan 1, 2026) removes JADU owner-occupancy only when the JADU has its own bathroom; if it shares a bathroom with the main home, the city can still require owner-occupancy
- Take advantage of SF fee waivers — the city offers significant reductions on permit and impact fees for ADUs 750 sq ft or less of interior livable space
- Garage conversions in SF are popular: existing non-conforming setbacks are grandfathered in
- The CalHFA $40K ADU grant is currently closed (funds exhausted December 2023) — check CalHFA.ca.gov/adu for any future funding rather than counting on it
ADU Builders in San Francisco
Looking for an ADU builder in San Francisco? ADU projects need a contractor experienced with local zoning, the permit process, and utility connections — not every general contractor has built one. We match San Francisco homeowners with experienced local ADU contractors who provide free, no-obligation quotes. Getting at least three bids typically saves 20-40% on the same scope.
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- Design an ADU that meets City codes | SF.gov Planning Department — Accessed 2026-02-24
- Accessory Dwelling Unit (ADU) | SF.gov Planning Department — Accessed 2026-02-24
- Get a building permit for an ADU | SF.gov Planning Department — Accessed 2026-02-24
- Angi — ADU Construction Cost Data Market Data — Accessed 2026-02-24
- Angi — Local ADU Contractor Costs Market Data — Accessed 2026-02-24
- Zillow Rental Manager — Market Rent Data Market Data — Accessed 2026-02-24
- HUD Fair Market Rents Government Data — Accessed 2026-02-24
- Prepare for an ADU project | SF.gov Planning Department — Accessed 2026-02-24
- California ADU Handbook — HCD Government Data — Accessed 2026-02-24
- California HCD — Accessory Dwelling Unit Handbook (updated March 2026) Government Data — Accessed 2026-06-28
- CA SB 543 (2025-2026) — Accessory dwelling units and junior accessory dwelling units (full bill text) Government Data — Accessed 2026-06-28
Frequently Asked Questions
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