ADU Permit in San Francisco, CA
Permit Summary
ADU Types & Property Eligibility
ADU Type Rules
San Francisco offers separate State and Local ADU paths; the number and configuration of units depend on the chosen program and existing/proposed dwelling type. State paths recognize converted, detached, attached and junior ADUs (JADUs). A JADU is contained within a single-family residence and is limited to 500 square feet. A State attached ADU uses a separate allowance from the combinable streamlined detached, converted and JADU types.
Lot / Zoning Eligibility Rules
The lot must be in a zoning district permitting residential use and contain an existing or proposed single-family or multifamily dwelling. State ADUs are reviewed under Section 207.2 and State law; Local ADUs under Section 207.1 and applicable local standards. The property's legal dwelling count, rear-yard conditions, historic status, tenancy and any other site constraints affect the available pathway.
Size, Height & Placement
Setback Rules
State new detached and attached ADU additions generally require four-foot side and rear setbacks; qualifying conversions within an existing building and qualifying same-size, same-location replacement structures do not require new setbacks. Local detached rear-yard ADUs generally require four-foot rear and side setbacks; Local interior conversions and expansions are governed by existing/buildable envelope and applicable local provisions.
Lot Coverage / FAR Rules
For State ADUs, San Francisco cannot apply floor-area ratio, lot coverage, open-space, minimum lot size or similar development standards so as to prohibit an otherwise qualifying ADU of at least 800 square feet with a 16-foot height and four-foot side/rear setbacks. Local ADUs remain subject to applicable zoning standards and any available waivers or exceptions under Section 207.1.
Attached ADU Rules
State attached ADUs expand or form part of a primary residential building and are available under the non-streamlined State provisions; the limit is one attached ADU instead of a combination of State streamlined units. The City's State bulletin specifies up to 25 feet in height, four-foot side and rear setbacks for portions outside the buildable area and the greater-of-50%-or-standard area limits. A Local attached/interior ADU follows Section 207.1 and the applicable Planning approval process.
Detached ADU Rules
A State detached ADU is a freestanding dwelling on a lot with an existing or proposed home. Single-family State units are generally limited to 850/1,000 square feet by bedrooms; existing multifamily properties can use the additional detached-unit allowance. State setbacks are generally four feet from side and rear boundaries, with qualifying existing-structure replacement exceptions. Local rear-yard detached ADUs have separate size, height and site rules. New freestanding ADUs cannot install new gas appliances under DBI guidance.
Conversion ADU Rules
The State Program allows a conversion within eligible existing or proposed residential space, including a qualifying accessory structure; up to 150 square feet of expansion of an existing accessory structure may be used solely for entrance and exit. Existing multifamily State conversions must use non-livable space and cannot take area from an existing dwelling or convert commercial space. Local interior ADUs follow Section 207.1, including protections for existing tenant housing services; permitting is also necessary to legalize unauthorized units.
Design, Occupancy & Parking
Design Standards
ADUs must meet adopted building, fire, housing, energy and objective Planning standards that apply to the selected program. DBI requires independent access, sufficient room dimensions, light, ventilation and safe exit routes. Many plan sets must be stamped by a licensed design professional, with limited exceptions. State streamlined ADUs are not subject to discretionary design review or Planning Code Section 311 neighborhood notification; historic-resource and applicable objective safety protections can still apply.
Owner Occupancy Rules
An ordinary ADU does not have a general owner-occupancy requirement. A State JADU that shares sanitation facilities with the principal single-family residence requires an owner to occupy either the main dwelling or JADU and a recorded deed restriction under the City's current State ADU bulletin. Requirements differ where a JADU has its own sanitation facilities.
Parking Rules
San Francisco Planning Code Section 151.1 generally does not require off-street accessory parking for any use, including an ADU. State ADUs are not required to replace off-street spaces removed through garage or covered-parking conversions. Any voluntarily provided parking remains subject to applicable design and access standards.
Rental / Short-Term Rental Rules
Under the State ADU program, rental terms must exceed 30 days; ADUs cannot be used as short-term vacation rentals. Local ADUs also prohibit tourist/short-term use and can be subject to the City's rent-stabilization ordinance, recorded restrictions and tenant protections, depending on the project and entitlement. Rules on occupancy, tenant notices and rental agreements vary by program.
Separate Sale Rules
Qualifying State ADUs may be separately sold or conveyed as condominium units under the City's Section 207.4 pathway. SF Planning identifies eligibility only for lots with four or fewer existing dwellings and ADU construction applications filed on or after May 1, 2025; no more than one ADU may qualify, and JADUs are excluded. For existing buildings the qualifying ADU is detached and, for multifamily buildings, existing units must already be condominiums; for new proposed single-family or entirely condominium multifamily buildings, attached or detached State ADUs may qualify. Ordinary separate lot subdivision or sale is not automatic.
Address, Utilities & Trade Permits
Utility Connection Rules
The ADU must have independent electrical wiring and appropriate access to circuit protection. Existing water, sewer, electrical or gas capacity must be evaluated and service changes coordinated with the San Francisco Public Utilities Commission and relevant providers such as PG&E. A new freestanding detached ADU cannot include new gas appliances and must be all-electric under current DBI guidance. Larger multifamily projects or new fire-suppression requirements may require water-service upgrades.
Trade Permit Rules
Electrical, plumbing and mechanical permits and related plan checks/inspections apply where the ADU's work includes those trades; the building permit fee schedule excludes these separate trade-permit fees. Electrical distribution and water/sewer work, new HVAC, ventilation or fire-protection work can require additional permits or agency signoffs depending on construction scope.
Fire, Energy & Special Requirements
Fire / Life Safety Rules
The ADU must provide compliant egress, emergency escape/rescue openings as applicable, fire-resistance-rated separations, smoke and carbon-monoxide alarms and fire-department access. DBI notes that sprinkler, fire-alarm and related water-capacity improvements can be required in certain additions to multifamily buildings, depending on unit count, occupancy classification, story count and location of bedrooms and exits. Fire Department review can be required.
Energy / Solar Rules
ADU work must satisfy the 2025 California Energy Code applicable to permits filed in 2026 and relevant San Francisco energy/green-building standards. New detached ADUs generally trigger the new-construction solar photovoltaic requirements unless a code exception applies; additions and conversions are evaluated under applicable alteration/addition rules. DBI calls for energy inspections and requires new freestanding ADUs to be all-electric rather than installing new gas appliances.
Special Area / Overlay Rules
Properties in historic or conservation districts or with designated historic resources may be subject to applicable objective historic-preservation standards; some State ADU proposals on such parcels must avoid adverse impacts on protected resources. Local ADUs may need additional review for required tenant protections, rear yards, street trees, structural/seismic conditions and other site-specific restrictions. New ADUs must also comply with building/fire requirements that are not displaced by the zoning exemptions.
Development / Impact Fee Rules
Under SF Planning's current State ADU guidance, ADUs and JADUs smaller than 750 square feet of interior livable area, or located on lots with three or fewer existing dwelling units, are exempt from development impact fees. When applicable, impact fees are proportionate to the ADU area relative to the primary dwelling. Exemptions from impact fees do not waive DBI plan review, building permit or applicable trade and utility fees.
Preapproved Plans
Preapproved Plan Rules
DBI has a Detached Accessory Dwelling Unit Pre-Approval Application for standardized detached ADU designs. Pre-approval concerns the model plans; an owner must still apply for the project-specific building permit and satisfy lot, foundation, utilities, zoning, engineering and inspection requirements. No universal plan or fixed approval time applies to every site.
Permit & Review Path
Permit / Review Path
Choose the State or Local ADU program and prepare plans. State ADUs receive ministerial review, with eligible cases potentially reviewed through the Permit Review Roundtable and without Planning Code Section 311 notice or discretionary review. Local Program ADUs ordinarily must first submit a Planning Project Application (PRJ), obtain a Planning Approval Letter, and then file that letter and plans for DBI building permit review. Complete required Fire, Public Works, PUC, trade and other agency coordination before issuance; arrange inspections during construction.
Inspections
Inspection Stages
DBI inspects permitted construction, including applicable foundation/structural and framing work before concealment, rough electrical/plumbing/mechanical work, energy-code compliance and fire/life-safety items, followed by required final building and trade approvals. The exact sequence depends on whether the ADU is new construction, an addition or a conversion, and on whether fire sprinklers or other special work is included.
What You Need Before Applying
Requirements
Establish eligibility under either the State-Mandated ADU Program (Planning Code Section 207.2) or Local ADU Program (Section 207.1); submit plans and obtain DBI building permit approval. Provide independent living facilities and an entrance and meet applicable zoning, structure, life-safety, energy, accessibility where applicable, and utility requirements. Local Program applicants must complete the separate Planning review and any required tenant/Rent Board documentation before DBI submission.
Exemptions
There is no general exemption from obtaining a building permit to establish a new or legalized ADU. Qualifying State ADUs receive exemptions from some zoning restrictions, neighborhood notification and discretionary review; qualifying projects may be exempt from development impact fees, but those exemptions do not eliminate the building permit. The State pathway for some unpermitted ADUs built before January 1, 2020 still requires legalization approval.
Required Documents
Building permit application and architectural plan set generally showing the site, existing and proposed floor plans, entrances, elevations, sections, and unit layout; structural plans/calculations when work affects the structure; applicable energy, fire/life-safety, electrical, plumbing, mechanical and utility information. Local Program applications also require a Planning Project Application, supporting drawings and ultimately the Planning Approval Letter; tenancy-related declarations and additional site-specific documentation may be required.