Pre-Approved ADU Plans, City by City

A pre-approved plan is the closest thing to a shortcut that exists in ADU permitting. The city has already reviewed the building against the code, so your application skips most of plan check and goes straight to the questions that are actually about your lot.

The catch is that the programmes vary from genuinely excellent to a web page with nothing on it, and the marketing around them is worse than the programmes themselves. I read every city page below directly rather than taking anyone's summary, and in three cases what the city publishes contradicts what gets repeated about it.

Every California City Must Have a Programme. Not Every One Has Plans.

This is the part almost nothing online explains properly, and it decides what you should expect when you search your own city. Government Code section 65852.27, added by AB 1332 and effective January 1, 2025, requires each local agency to develop a program for the preapproval of accessory dwelling unit plans, to post the preapproved plans on its own website, and to approve or deny an application using a preapproved plan within 30 days of a complete submittal.

Read what that compels and what it does not. It compels a process and a page. It does not compel a catalogue. A city can be in full compliance with a live preapproval process, a published web page, and zero plans on it, because nobody has yet submitted a design for preapproval or none has cleared review.

So when you land on your city's preapproved ADU page and find it empty, that is not necessarily a broken city. It is the statute working exactly as written. What it means practically is that your options are a neighbouring jurisdiction's plans where those are accepted, a designer who will take their own plan through preapproval, or a custom set.

How to Actually Use One

The sequence matters more than the choice of plan, and getting it backwards is the most common way people lose the saving they came for.

Pick the design first, from the city's own list rather than from a builder's page. Then contact the plan preparer and agree the licence fee and what they will do for it, specifically whether they submit the plans and pull the permit. Then find a builder. If you start with a builder, you will very often end up being steered toward a custom design that firm already knows how to build, and the weeks you were saving quietly evaporate.

Second thing: do not modify the plan. Encinitas disqualifies a modified plan outright and Sacramento County does not allow modifications at all. Even where a city is more relaxed, a change means a fresh review of the thing that was supposed to be pre-reviewed.

Third, budget for the site-specific work regardless. Every programme on this page still requires a site plan, setbacks, utility connections and usually a foundation design for your particular soil. A pre-approved plan removes the architectural review, not the engineering.

If none of these programmes covers your city, our own ADU floor plans are a reasonable place to work out what you want before you pay a designer to draw it. They are concept layouts rather than permit sets, which is the whole distinction this page is about.

Frequently asked questions

What are pre-approved ADU plans?

They are complete construction plan sets that a city has already reviewed for code compliance, so an application using one skips most of plan check. You still submit site-specific documents showing where the unit sits on your lot, your setbacks, your utility connections and usually your foundation design. Pre-approved means the building has been reviewed, not that your project has.

Does every California city have pre-approved ADU plans?

Every local agency is required to have a programme, but plenty of those programmes have nothing in them. Government Code section 65852.27, added by AB 1332 and effective January 1, 2025, requires each local agency to develop a preapproval process for ADU plans and to post the preapproved plans on its website. The statute compels the process, not a catalogue, so a city can comply fully and still publish an empty list. Sacramento is the clearest example on this page.

How much do pre-approved ADU plans cost?

It depends who owns the plan. City-owned plans are usually free to download, as in Encinitas and unincorporated Sacramento County. Where the plan belongs to a private designer, as in Seattle and most of San Jose and Los Angeles, you license it from that designer at a price they set. In every case you are still paying separately for the site-specific work, the permit fees and the build itself.

How much time does a pre-approved plan actually save?

Weeks, and occasionally months, but on plan check rather than on the whole project. Seattle quotes 2 to 6 weeks to permit against many months for a custom design. San Jose says a permit can issue the same day as the plan review meeting when the site-specific package is complete. Los Angeles standard plans commonly run 3 to 4 weeks of plan check against 4 to 10 for custom. None of that shortens construction.

Can I modify a pre-approved ADU plan?

Usually not without losing the benefit. Encinitas states that modifying a City-approved plan disqualifies it as a PRADU and sends the project through standard review, and Sacramento County does not allow modifications to its Shelf Ready plans at all. If you need changes, go back to the plan preparer for an updated set rather than redlining it yourself, because a modified plan is a custom plan in the eyes of the counter.

If I were starting today in a city with a real catalogue, I would use it and stop optimising. The design compromise of building somebody else's layout is almost always smaller than the compromise of waiting four more months.