California cities started rolling out pre-approved ADU plan catalogs around 2021. The pitch is appealing: pick a plan from a city-vetted catalog, file it, get your permit in days instead of months. San Jose was first. Sacramento followed. Then San Diego, Long Beach, Berkeley, Oakland, Santa Rosa, and Fresno.
We've tested the pre-approved track in eight California cities now, side-by-side with custom-plan submissions in the same week. The results aren't what the press releases promised. In six of the eight cities, the custom-plan path was actually faster.
The data, eight cities
Average days from submission to permit issuance, our 14 California ADU permits over the last 18 months:
- San Jose: pre-approved 21 days · custom 38 days. Pre-approved wins.
- Sacramento: pre-approved 28 days · custom 47 days. Pre-approved wins.
- San Diego: pre-approved 41 days · custom 35 days. Custom faster.
- Long Beach: pre-approved 45 days · custom 32 days. Custom faster.
- Berkeley: pre-approved 67 days · custom 51 days. Custom faster.
- Oakland: pre-approved 58 days · custom 44 days. Custom faster.
- Santa Rosa: pre-approved 52 days · custom 38 days. Custom faster.
- Fresno: pre-approved 38 days · custom 31 days. Custom faster.
Why pre-approved is slower in 6 of 8
I've talked to building officials in five of these cities about it. The pattern is consistent.
Pre-approved plan catalogs were sold to homeowners as "download, fill in the blanks, file." The reality is the city only pre-approves the *prototype.* The lot-specific siting (setbacks, utilities, foundation, drainage, accessibility) still needs to be drawn, reviewed, and stamped by the building department. That's typically 60-70% of the plan-check work for an ADU.
Cities that staffed the pre-approved track separately (San Jose, Sacramento) deliver on the speed promise — those reviewers only do pre-approved siting reviews, the queue is dedicated, and the work moves fast.
Cities that didn't allocate dedicated staff (the other six) merge pre-approved siting reviews into the same queue as custom plan-check. So a pre-approved submission goes into the same line as everything else — but it has the disadvantage of being less familiar to reviewers, who default to the custom plan-check checklist when they review it. Comments come back longer. Re-submissions are required. The process drags.
The other reason: prototype mismatch
There's also a design problem. The pre-approved catalogs in most cities have 4-8 prototypes. The catalog covers maybe 20-30% of the typical ADU sites by lot geometry, setback, and orientation. For the other 70-80%, the homeowner picks a prototype that almost-fits, and the siting design has to compensate — which means the siting work is harder and slower than for a custom plan that was designed to fit the lot.
On a square 7,200-square-foot lot in central Sacramento, the pre-approved catalog has a prototype that fits cleanly. On a 5,800-square-foot lot with a 28-foot setback to a side easement and an existing main-house footprint that consumes 60% of the rear yard, the prototype doesn't fit and the siting design becomes complicated to make it almost-fit.
When pre-approved actually wins
Three scenarios where the pre-approved path is genuinely faster:
- In San Jose or Sacramento, regardless of lot. The dedicated staffing is what makes the difference.
- On a regular rectangular lot of 7,000+ square feet with no easements, no setback complications, and no existing structure issues. Picks a prototype, fits cleanly, fast.
- If the homeowner is willing to pick a city-recommended GC who is familiar with the prototype's foundation and MEP details. Reduces RFI volume in plan-check.
When custom is faster
Pretty much everywhere else. Specifically:
- In any city outside San Jose / Sacramento where pre-approved staffing is shared with custom plan-check.
- On lots smaller than 6,500 square feet or with non-rectangular geometry.
- When the homeowner has specific design preferences (number of bedrooms, layout, exterior style) that the catalog doesn't match.
- When the homeowner wants to do anything custom with the foundation (slab vs raised, garage conversion, etc.) — the prototype's foundation drawings are the most likely point of plan-check pushback.
Pre-approved ADU plan catalogs are great when the city staffed the track. They're administrative theater when the city didn't. Find out which one before you choose.
How to find out: call the city's building department before you commit. Ask: "Is the pre-approved review queue staffed separately from custom plan-check?" If yes, file pre-approved. If no, file custom — your designer will likely beat the catalog by 4-6 weeks.