Quick answer
Quick answer: Choose a San Francisco ADU contractor with relevant local experience, a verified California license, and a written plan that assigns responsibility for permits, inspections, construction, payments, changes, and closeout.
Get Matched With a San Francisco ADU Contractor
A qualified contractor should clearly explain who will prepare plans, submit permits, respond to review comments, coordinate trade work, schedule inspections, correct deficiencies, and assemble final records.
Put those responsibilities in the construction contract. Eligibility, permit approval, price, and timing depend on the property, design, agency review, and scope of work.
Mr. Nailed It connects homeowners with vetted independent contractors. It does not prepare plans, submit permits, schedule inspections, or perform construction. You can also explore how to find a California ADU contractor.
What an ADU Contractor Should Help Coordinate
San Francisco's Department of Building Inspection approves plans, issues construction-related permits, and reviews proposed construction for compliance with safety requirements (SF DBI).
DBI inspections determine whether work complies with code requirements and the approved permit scope (SF DBI). Your agreement should identify who handles each step before work begins.
- Review the site and proposed ADU location.
- Coordinate design, engineering, and permit-document inputs.
- Identify who submits applications and responds to plan-review comments.
- Sequence construction and licensed trade work.
- Schedule required inspections and document corrections.
- Maintain permits, inspection records, changes, and closeout documents.
Where a San Francisco ADU Can Be Created
San Francisco Planning identifies basements, garages, and backyards as potential locations for new housing (SF Planning). That does not mean every basement, garage, backyard, or proposed design is eligible.
California recognizes accessory dwelling units and junior accessory dwelling units as housing options. ADUs may also be called in-law units, granny flats, backyard cottages, or secondary units (California HCD).
Note: Feasibility depends on the property and project-specific planning, building, utility, and design requirements. Ask San Francisco Planning and DBI to confirm what applies to your address and proposal.
San Francisco ADU Permit Process
Plan to obtain the permits required for the proposed construction. DBI approves plans and issues construction permits in San Francisco; confirm project-specific requirements with DBI and Planning (SF DBI).
- Assess the property and define the proposed ADU.
- Develop plans and obtain necessary design or engineering input.
- Confirm the applicable review route with DBI and Planning.
- Register and apply through the PermitSF portal.
- Respond to agency comments and revise documents when required.
- Obtain permits before beginning the permitted work.
- Complete construction and required trade work.
- Pass required inspections and retain closeout records.
Applicants can register and apply through PermitSF (SF DBI). Some projects may qualify for ministerial, non-discretionary review, but not every proposed ADU will qualify (SF Planning).
Codes That Apply to Applications Filed in 2026
Applications filed on or after January 1, 2026 (2026-01-01), must use the 2025 California Codes and 2025 San Francisco Code Amendments. San Francisco states that there is no grace period (SF DBI).
California's 2025 Building Energy Efficiency Standards also took effect January 1, 2026 (California Energy Commission).
Ask the designer and contractor which code editions appear on the plans. Confirm current filing requirements with DBI before submission, particularly if design work began under an earlier code edition.
The California Department of Housing and Community Development's official ADU resource and handbook was updated in March 2026.
Inspections and Permit Tracking
Building, plumbing, mechanical, and electrical inspections can be scheduled and paid for through DBI (SF DBI). The contract should assign that responsibility rather than leave it assumed.
Ask how failed or correction inspections will be recorded, who will complete corrective work, and who will request reinspection. The payment schedule should not get ahead of documented progress.
San Francisco provides systems for checking permit-application status and permit history. DBI also maintains records that include plans, permit applications, and job cards (SF DBI).
How to Check an ADU Contractor
Before signing or paying, verify the contractor through the Contractors State License Board. CSLB licenses and regulates California's construction industry and provides license-check and contractor-search tools (CSLB).
- Confirm that the license is current and appropriate for the proposed scope.
- Check the business name and license details against the proposed contract.
- Ask who will manage permits, inspections, subcontractors, changes, and final records.
- Check DBI's Expanded Compliance Control list for the contractor, architect, and engineer.
- Request a written description of included, excluded, and property-dependent work.
DBI provides an Expanded Compliance Control list that homeowners can use to confirm a proposed contractor, architect, or engineer is not listed (SF DBI). Vetting does not guarantee workmanship, approval, cost, or completion.
Contract and Payment Protections
CSLB identifies residential ADU construction as home improvement work subject to its stated contract and payment rules. Its guidance says the down payment should not exceed $1,000 ($1000) or 10% of the total contract price, whichever is less (CSLB).
According to CSLB, payments after the down payment must be clearly listed in the contract and based on the actual value of completed work or materials delivered to the home (CSLB).
- A detailed scope with clear exclusions and allowances
- A payment schedule tied to defined work or delivered materials
- A written change-order process
- A responsibility matrix for permits, inspections, and records
- A process for documenting corrections and disputed work
- A list of documents provided at closeout
Heads up: This summarizes CSLB guidance and is not legal advice. Review current CSLB requirements and ask a qualified attorney about contract terms or disputes.
Planning for Permit, Inspection, and Impact Fees
An ADU budget may need to account for design, engineering, construction, permits, inspections, Planning fees, impact fees, review corrections, and property-specific work. Applicable amounts depend on the proposal and agency review.
DBI publishes information about permit, inspection, and penalty fees (SF DBI). San Francisco Planning offers an interactive fee schedule and calculator for exploring Planning fees (SF Planning).
The city assesses impact fees on new development projects to support public services. Planning provides a Development Impact Fee Calculator for estimating applicable development-project impact fees (SF Planning).
Use the San Francisco ADU cost guide for broader budget planning. For statewide context, see California ADU cost and contractor rules.
Questions to Ask Before Hiring
- Have you completed comparable ADU work under San Francisco's current permit and code process?
- Who prepares and submits permit documents?
- Who responds to plan-review comments?
- Who schedules building, plumbing, mechanical, and electrical inspections?
- What work is included, excluded, or subject to further investigation?
- How will allowances, changes, corrections, and payment milestones be documented?
- How will subcontractors and trade work be coordinated?
- Which permits, inspection records, warranties, and other documents will I receive at closeout?
Related ADU Resources
Planning outside San Francisco? Compare the local process with the Los Angeles ADU contractor guide, Los Angeles cost guide, and Los Angeles construction guide.
San Francisco ADU Contractor FAQ
Frequently asked questions
How can I choose an ADU contractor in San Francisco?
Verify the California license, check DBI's Expanded Compliance Control list, and review relevant local ADU experience. Require a written scope that assigns responsibility for permits, inspections, trade coordination, changes, payments, and closeout.
Do I need a permit for a San Francisco ADU?
Plan on permits for the proposed construction. DBI approves plans and issues construction-related permits in San Francisco. Ask DBI and Planning to confirm the permits and review route required for your property and design.
Will every San Francisco ADU receive ministerial review?
No. San Francisco Planning says some projects may qualify for ministerial, non-discretionary review. Confirm eligibility with Planning for the specific property and proposal.
Who schedules ADU inspections?
DBI allows building, plumbing, mechanical, and electrical inspections to be scheduled and paid for through the department. The owner and contractor should state in writing who is responsible for scheduling each inspection.
How can I estimate San Francisco ADU permit and Planning fees?
Review DBI's permit and inspection fee information, Planning's interactive fee schedule, and the Development Impact Fee Calculator. Confirm project-specific amounts with the relevant city agency.