Guide
How long does an ADU take in San Diego, from permit to move-in?
The short answer
Expect roughly two years from permit submission to final inspection in the City of San Diego, plus the design time before you apply. A local builder's analysis of the City's permit records found an average of 21.8 months for ADUs and JADUs that reached final inspection, and about 24 months for detached new ADUs. State law sets the first clocks: 15 business days to tell you whether your application is complete, then 60 days to approve or deny it when a house already stands on the lot.
The stages, and what sets each clock
An ADU passes through the same stages wherever you build it. Some have a deadline in state or City law. Others have no official clock at all, and that is where most of the time goes.
| Stage | What sets the clock |
|---|---|
| Design and site work before you apply | No official clock. One local builder puts this stage at about six weeks to six months or more, depending on the plan, the utilities and the site. |
| Completeness check | State law gives the agency 15 business days to tell you in writing whether the application is complete, with a list of anything missing. If it says nothing in time, the application counts as complete. |
| Decision on the permit | 60 days from a complete application to approve or deny it when a house already stands on the lot. A denial must come with a full list of what to fix. If the agency misses the 60 days, the law treats the application as if it had said yes. |
| Preapproved plans | The City gives an application that uses a preapproved plan it accepts a 30-day review. You license the plan from its provider, and it must meet the codes in force when you submit. |
| Corrections and rechecks | In the City you cannot upload corrections until every review discipline has finished its cycle, and all responses go in as one file. Each recheck adds a cycle. |
| Permit issuance | The City publishes this queue weekly in business days. In the data current as of October 9, 2026, a Building Permit took about one business day to issue. |
| Construction | Substantial work must pass an inspection within 12 months of issuance, work cannot stop for 180 days, and a permit for a detached one- or two-family dwelling and its accessory structures expires three years after issuance. |
| Power | SDG&E asks for the ADU's own address before you apply for service and says to allow two weeks for its review. |
| Move-in | You need a certificate of occupancy before anyone lives in the ADU. |
The state deadlines, in plain terms
Every permitting agency in California must now answer an ADU application for completeness within 15 business days. If it finds gaps, it has to list them and explain how to fix them, and it cannot add new items when you resubmit. You can appeal an incomplete finding or a denial, and the agency must give a final written answer within 60 business days of your appeal.
The 60-day decision clock runs only once the application is complete, and only when a house already stands on the lot. If you apply for a new house and an ADU together, the agency may hold the ADU until it decides on the house. If you ask for a delay yourself, the clock pauses for that time.
These are the limits for the agency's review, not for your whole project. Design, corrections you make, construction, inspections and utility work all sit outside them.
What the City publishes each week
The City's Development Services Department posts a weekly snapshot of how long applications wait at intake, in review and at issuance. Intake and review are shown in calendar days from the day before. Issuance is shown in business days, with the number of projects waiting. The most recent data on the page was current as of October 9, 2026.
In the City's tables, a project counts as complete for review once its project set-up fees are paid, and first review starts from there. Recheck times start only after every document on the required submittal report is uploaded.
What the City's permit records show from start to finish
The City's weekly figures cover single steps, not the whole path. The closest thing to an end-to-end figure is an analysis of the City's public permit records by SnapADU, a San Diego ADU builder, covering about 10,000 ADU and JADU applications received from 2021 through 2025, with data last updated in June 2026. Treat it as one firm's reading of public data, not a promise.
- Average time from submission to final inspection: 21.8 months for all ADUs and JADUs, 20.5 months for conversions and additions, and 23.8 months (about 24) for detached new construction.
- Of the detached new ADUs submitted at least three years earlier, 74% had a permit and 43% had reached final inspection within three years. Of those submitted at least two years earlier, 24% had reached it within two years.
- Of the detached new ADUs that had held a permit for at least three years, about 76% had reached final inspection. About one in ten was cancelled or withdrawn after the permit was issued, and about one in ten showed no construction.
- For the ones that finished, the average from permit to final inspection was about 16 months.
Two caveats from the analysis itself. The clock starts at submission, so the design work before it is not counted. And the City does not record project type, so the firm sorted applications by keywords in the permit description, which is approximate.
From BHI's own permit record
The County of San Diego publishes its building permits as open data, with the contractor's license on each. These are BHI's recent ADU permits there, with the day each application opened and the day its permit issued. Plan review on the two detached and two-story projects took about seven months each; a junior ADU and a garage conversion went faster.
| Project | From application to permit |
|---|---|
| Two-story 1,152 sq ft detached ADU with a deck and a detached garage, North County Metro near Escondido | Opened November 27, 2023; issued July 12, 2024: about seven and a half months. Completed. |
| 498 sq ft junior ADU above the garage on the same lot | Opened December 26, 2023; issued April 10, 2024: about three and a half months. Completed. |
| 360 sq ft garage conversion on the same lot | Opened July 9, 2024; issued August 12, 2024: about five weeks. Completed. |
| 720 sq ft garage conversion with a 720 sq ft room above, Hidden Meadows | Opened January 10, 2025; issued August 1, 2025: about seven months. |
The design work before each application and the construction after each permit are not in the record, so these are plan-review times only. The County's clock, not BHI's, sets them: a complete application is decided within 60 days, but a detached ADU on a hillside lot usually goes through more than one round of corrections.
After the permit: keeping it alive to final inspection
- An application in the City closes if two years pass after it is deemed complete without a request to issue the permit. The Building Official can extend it up to two times, by up to 180 days each, in limited cases.
- Once issued, a permit becomes void if substantial work is not done and inspected within 12 months, or if work stops for 180 days. One extension of up to 180 days is possible, with a second in limited cases.
- If final inspection has not happened by the permit's expiration date, all work stops until a new permit is issued.
- SDG&E needs the ADU's address from the city or the County that issues the permit first, takes applications through My Project Center and says its timeline depends on the project's complexity.
What speeds it up, and what slows it down
- A complete first submittal. The City asks applicants to check the submittal manual and current forms before uploading, and staff screen every application for completeness.
- A preapproved plan the City accepts: the County's standard plans, Chula Vista's or Encinitas'. The City reviews those in 30 days.
- An older house. If a building on the lot is more than 45 years old, the City asks for the Assessor Building Record and a photographic survey with the application.
- One answer to all corrections. Responses from every discipline go in together, so a slow answer on one item holds up the rest.
What changes the answer
The figures above are the City of San Diego's. These are the cases where the clock runs differently.
Another city, or the unincorporated County
The state deadlines apply to all 19 permit authorities in the county, but each one runs its own queue. The County lists a permit center queue status page among its online services. The SnapADU figures cover the City of San Diego only.
The Coastal Overlay Zone
Most new ADUs in the City's Coastal Overlay Zone need a Coastal Development Permit. In the non-appealable area the City can issue it as a building permit when set findings are made. State law requires a decision on a coastal permit for an ADU within 60 days of a complete application, running alongside the ADU review.
A new house and an ADU together
When you apply for both at once, the agency may wait to decide on the ADU until it decides on the house. A certificate of occupancy for the ADU generally cannot come before the house's, except in some counties under a state of emergency declared since February 1, 2025 where the house was damaged or destroyed.
Fire hazard zones
In the City's fire hazard zones an ADU keeps 4-foot side and rear setbacks at any height, and the Fire Code Official may ask for more; the City's bulletin says Very High zones and its Municipal Code says High or Very High. A design that has to move can add a correction cycle.
A homeowners association
An HOA cannot take part in an agency's permit review. HCD's handbook lists an HOA review that runs past the 60 days given to agencies, or that significantly delays an ADU, as an example of an unreasonable restriction.
Utilities
SDG&E reviews applications in about two weeks once it has the ADU's address, but larger service work follows the project's complexity. Sewer, water and electrical upgrades found late can push back design.
How long our ADUs have taken
The part only a builder can add: how long BHI's own ADUs took from design to move-in, and where the time went.
On BHI's two most recent County ADUs, plan review ran about seven months each: the two-story detached ADU's application opened in November 2023 and its permit issued in July 2024; the solar ADU's opened in January 2025 and issued in August 2025. The junior ADU on the first lot took about three and a half months and its garage conversion about five weeks. Construction and final inspection times are not in the public record; BHI adds them as each project closes.
Next steps
Check who reviews your lot, get the documents together, then plan the budget around the timeline.