Your San Diego ADU Permit Now Has a Shot Clock

If you have ever submitted an ADU application and then waited — no comments, no status change, no idea whether anyone had opened the file — you know the most frustrating part of building a backyard home in California isn't the framing. It's the silence.

That silence now has a legal limit. A pair of state laws signed in October 2025 and in force through 2026 put hard, countable deadlines on how long a city can take with your accessory dwelling unit application, and they give you something to do when those deadlines pass. Here is how the clocks actually work, and how San Diego homeowners can use them.

Clock #1: 15 business days to tell you if your application is complete

The first stall in most ADU projects isn't plan check — it's the limbo before plan check, when nobody will confirm whether your submittal was even accepted.

Under changes made by Senate Bill 543, a permitting agency must decide whether your ADU application is complete and give you written notice of that determination within 15 business days of receiving it. If the application is incomplete, the agency has to hand you a list of exactly what's missing.

Two details in that law matter more than they first appear:

• Miss the deadline, and the application is deemed complete. If the agency never issues a timely determination, the law treats your application as complete for purposes of the review statute.
• The list is the whole list. When you resubmit to cure the items they flagged, the agency cannot turn around and require something that wasn't on the list it gave you. No moving targets.

That second point is the one that saves months. The classic ADU delay pattern is three rounds of comments where each round introduces a brand-new request. State law now closes that door.

Clock #2: 60 days to approve or deny

Once your application is complete, the agency must approve or deny it within 60 days. If it doesn't act in that window, the application is deemed approved.

Just as important, ADU applications are still required to be considered ministerially, without discretionary review or a hearing. There is no design board, no neighbor hearing, no discretionary finding for a compliant ADU. The 60-day rule is the enforcement backstop on that promise — not an exception to it.

A word of caution from experience: "deemed approved" is a legal remedy, not a plan. Relying on a deemed approval to start construction is a genuinely risky way to build, because you may end up arguing about the scope of what was approved at exactly the moment you have a crew on site. The deadlines are far more valuable as leverage to get a real, documented approval issued than as a shortcut around one.

Clock #3: when plan check stalls, you can bring your own plan checker

This is the newest and least-known tool, and it's the one that changes the dynamic most.

AB 253 lets an applicant hire a certified third-party plan checker when a jurisdiction is slow. It applies to residential building permits for new construction, additions, and remodels of buildings with 1–10 dwelling units under 40 feet tall — which covers essentially every ADU project.

The mechanics are specific, so follow them exactly:

1. The trigger. Either the agency gives you an estimated review timeframe longer than 30 business days, or it simply fails to determine compliance within 30 business days of deeming your application complete.
2. Your notice. You must notify the agency that you're exercising this right no later than five business days after that trigger. Miss this window and you lose the option.
3. The turnaround. Once the agency receives the private plan checker's report, it has 10 business days to either issue the permit or notify you of specific non-compliance. If it misses that and the provider's affidavit states the plans comply, the permit is deemed approved.

The City of San Diego's Development Services Department publicly acknowledges this pathway, noting that private professionals may perform plan checks on 100% residential projects of 1–10 units when its own reviewers don't finish within 30 business days. The provision runs through January 1, 2036.

The five-business-day notice requirement is the part homeowners miss. It means someone has to be watching your file closely enough to catch the trigger the week it happens — which is a large part of what a construction manager is actually for. We walk through how we track these milestones on our process page.

What changed in San Diego this month

Separately from the state timelines, San Diego's 2026 Land Development Code update took effect in July 2026 for properties outside the Coastal Zone. Per the city's own regulatory summary, it clarifies several things worth knowing before you design:

• Unit counts on single-family lots: one JADU, one converted ADU (a garage conversion, for example), and one detached or attached ADU.
• Multifamily properties: up to eight detached ADUs, provided the number doesn't exceed the count of existing units.
• Fire hazard zones: ADUs in high and very high fire hazard severity zones must hold a four-foot setback from side and rear property lines.
• Height in single-family zones: detached ADUs are held to a two-story maximum structure height.

If your property is in the Coastal Zone — much of Carlsbad, Encinitas, and the coastal strip — these particular changes don't apply to you in the same way, and coastal review adds its own layer. That distinction is worth confirming before you spend money on drawings.

How to actually use these deadlines

Rights you can't prove are rights you don't have. Three habits make the difference:

Date-stamp everything. Submit through the portal, save the confirmation, and log the date you submitted, the date the completeness determination was due, and the date it arrived. The clocks run on business days, so count them deliberately.

Read the incomplete list like a contract. When comments come back, compare each new request against the original list. If something new appears on round two, say so in writing and cite the resubmittal limitation.

Reduce the surface area for comments. The fastest permit is the one with the fewest things to argue about. Standardized, pre-reviewed drawings cut review cycles substantially — that's the whole idea behind our pre-approved plans, and it's why a clean submittal usually beats a clever one.

For the underlying state rules in plain language, California's Department of Housing and Community Development maintains an official ADU Handbook, updated in March 2026, with an addendum summarizing the law changes that took effect January 1, 2026. It's dry, but it's authoritative, and it's free.

Where we fit

Casita ADU is a construction management agency, not a general contractor. We represent the homeowner: we assemble the team, manage the submittal, track the clocks described above, and push when a deadline passes. Our services page lays out exactly what that covers and what it doesn't.

If you're staring at an application that hasn't moved in weeks — or you're about to submit one and would rather not find out the hard way — book a free site walk. We'll look at your lot, tell you honestly what's feasible, and map the timeline you should actually expect in your jurisdiction.

Deadlines only work for the people who know they exist. Now you do.