AB 1308, which took effect January 1, 2026, requires building departments to conduct inspections within 10 business days of receiving a notice of completion for certain residential projects. If they don't, it's a violation of the Housing Accountability Act—the same statute that cities actually fear because it carries mandatory attorney's-fee awards and can override local denials. California now puts an enforceable deadline on the end of the permit process, not just the beginning.
Who AB 1308 Covers
The 10-business-day clock applies to residential-only buildings with no floor used for human occupancy more than 40 feet above ground level. Specifically, it covers new residential construction of one to 10 units and additions to existing buildings with one to nine units that add more units (up to 10 total). That scope captures nearly every ADU, every detached casita, every duplex, triplex, and small multifamily project in California. It does not cover mixed-use buildings, single-family remodels that don't add units, or buildings with occupied floors more than 40 feet above ground.
The test is whether any occupied floor sits more than 40 feet above ground level, not the roof height, so most two- and three-story homes, ADUs and townhomes qualify. Mixed-use buildings don't. The law is aimed at the housing types that state legislators want to move faster: backyard cottages, missing-middle infill, and the kind of small multifamily that pencils on standard residential lots.
What the 10-Business-Day Deadline Actually Means
Once the building department receives notice that the permitted work is complete, it has 10 business days to conduct the inspection, not just schedule it. Not 10 calendar days, so weekends and holidays don't count. The law doesn't define the notice, so ask your department how it wants completion reported. If the 10th business day passes without an inspection, the department is in violation of the Housing Accountability Act.
What does an HAA violation get you? The Housing Accountability Act allows developers to sue and recover attorney's fees if a local agency violates the statute. It's not an automatic fine, but it gives you a credible enforcement tool. If your client is sitting on a finished ADU in San Diego or a triplex in Sacramento and the building department is two weeks past the deadline, your land-use attorney can send a letter citing AB 1308 and the HAA. That letter puts the city on notice.
We're not litigators, but cities respond to statutory hammers. AB 1308 created one.
Why This Matters More Than Plan-Review Timelines
California already has SB 35 and other laws that set deadlines for approving housing projects. AB 1308 is different because it governs the inspection after construction is done. That's the moment when your client has the most money on the line—the GC has demobilized, the loan is in its final draw, and every day of delay costs rent or sale proceeds.
A three-week slip during plan review is annoying. A three-week slip after you've filed for final inspection is a financial emergency. If you're a general contractor with a crew rolling onto the next job, you can't send them back for a punch-list fix if the city takes a month to tell you what's wrong. If you're an ADU buyer trying to get a tenant in before the first mortgage payment, every week past completion is money out of pocket.
AB 1308 doesn't speed up plan review, and it doesn't fix understaffed building departments. But it does mean that once you're done building, the city has to inspect within 10 business days. For projects in the one-to-ten-unit range, the final-inspection wait now has a deadline.
What Happens If You Fail the First Inspection
The 10-business-day clock is for conducting the inspection, not for issuing the certificate of occupancy. If the inspector shows up on day eight and red-tags your electrical panel, you still have to fix it and call for a re-inspect. The law doesn't say the city has to re-inspect in another 10 days, so expect the normal queue for corrections. The penalty is for not showing up, not for failing you.
That said, AB 1308 makes the first-inspection date predictable, which means you can plan your punch-list window and your contractor's availability. You're not waiting in limbo wondering if the city will show up next Tuesday or next month.
How to Adjust Timelines for California Projects
For ADUs, duplexes, or small multifamily in California, budget 10 business days from notice of completion to final inspection—and file the notice as soon as the GC says the site is ready. If you're conservative, add a few days for the city to process the notice itself, but the statute is clear: the clock starts when they receive it, not when they acknowledge it.
For projects near a lease date or a sale closing, we recommend filing the notice even if there are minor punch-list items left, as long as life-safety systems are done. The inspector will catch the loose outlet cover, but you've locked in your inspection date. You can fix small stuff and call for a same-day re-inspect if the department allows it, or schedule the correction and re-inspect within the normal window. Either way, you're not burning three weeks waiting for the first visit.
The Bigger Picture: HAA Enforcement for Housing Production
AB 1308 is part of a 2026 package of California housing laws that incrementally tighten the screws on local agencies that slow down residential development. AB 253 lets residential permit applicants hire a private plan checker when the city's plan-check estimate runs past the law's limit, or the city gives no estimate. SB 79 sets minimum height and density standards for housing near major transit stops in the state's urban transit counties, starting July 1, 2026. AB 920 will require cities and counties of 150,000 or more to offer an online portal for housing development applications, with deadlines starting in 2028.
None of these laws are silver bullets. But together they create a statutory framework where delays have consequences and developers have recourse. For the kind of infill housing California says it wants—ADUs, casitas, triplexes, transit-oriented apartments—AB 1308 puts a deadline on the final-inspection wait.
If you're planning a home, an ADU or an addition in California, talk to us—California's new timelines mean accuracy up front pays off faster than it used to. We take projects in all 50 states; apartment buildings we refer to a registered architect.