How long does it take to get an ADU permit in California?

State law requires ministerial approval or denial within 60 days of a complete application (Gov. Code §66317) — and a 'deemed approved' backstop if the city misses the clock. In practice, plan for 2–4 months from first submittal to permit issuance: completeness review, 1–3 plan check rounds with corrections in between, and scheduling. Pre-approved ADU plans can shorten the review to 30 days for the site-specific portion.

What is the 60-day ADU approval rule?

California law (Gov. Code §66317) requires cities to approve or deny a complete ADU application ministerially — no hearing, no discretionary review — within 60 days. If the city does nothing, the application is 'deemed approved.' A separate clock requires the city to tell you within 15 business days whether your application is complete (SB 543, 2026). These are decision clocks, not issuance clocks — corrections cycles pause them.

Do pre-approved ADU plans really speed up permits?

For the site-specific portion, yes — state law (AB 1332) requires staff to approve or deny the site-specific application for a detached ADU in 30 days when the pre-approved plan details are unchanged. You still need soils, site plan, utilities, and foundation review. Cities like Riverside, Salinas, Garden Grove, and Anaheim publish the plan sets; the 30-day clock covers only the unchanged portions.

How Long Does an ADU Permit Take? The Timeline Nobody Puts in the Quote

Published: 17 Oct 2026 · Last verified: 9 Oct 2026 · Next review: Jan 2027 Timelines vary by city and project. Changes are logged in Corrections.

“Six months, start to finish.” It is the most common sentence in ADU sales, and it is missing three to four months of paper.

Nobody lies, exactly. The six months usually describe construction — the part with hammers. Before the hammers come the drawings, the submittal, the plan check rounds, the corrections, the resubmittals, and the inspections scheduled between them. This post maps the paper timeline phase by phase, with the statutory clocks California actually guarantees and an honest account of where the clocks stop.

The statutory clocks

California law gives ADU applicants three enforceable timelines. Know them before you submit anything:

Clock	What	Law
15 business days	City must tell you whether your application is complete — with an exhaustive list of anything missing	Gov. Code §66317 (SB 543, 2026; previously 30 days)
60 days	City must approve or deny a complete application, ministerially — no hearing. Miss it and the application is “deemed approved”	Gov. Code §66317
30 days	Site-specific review of a pre-approved ADU plan (detached, unchanged details)	AB 1332 (Gov. Code §65852.27)

Two fine-print notes. First, the 60-day clock runs from a complete application — the completeness review is its own phase, and every corrections round restarts portions of it. Second, “deemed approved” is real law, but invoking it against your own building department is a relationship decision; most applicants treat the clock as leverage for follow-up, not litigation.

The realistic timeline

Here is what the phases actually look like, with honest ranges:

Phase	Typical duration	What happens
Design & engineering	4–12 weeks	Architect/drawings, Title 24 energy, structural. Pre-approved plans cut this sharply but site-specific work remains.
Completeness review	1–3 weeks	City checks the submittal against its checklist. Statutory max: 15 business days.
Plan check, round 1	3–6 weeks	Structural, fire, planning, public works review in parallel.
Corrections	2–4 weeks	You (or your designer) answer every redline. This is the applicant’s clock, not the city’s.
Plan check, rounds 2–3	2–4 weeks each	Each round should be shorter — in practice, new comments appear.
Permit issuance	1–2 weeks	Fee payment, final stamps.
Submittal → permit	~3–6 months typical	The honest range for a custom design.
Construction	5–8 months	The “six months” in the quote — for the build only.
Inspections	During construction	Foundation, framing, rough utilities, final. Scheduled 1–2 weeks out in busy jurisdictions.
Utility hookup	Up to 9–12 months	The forgotten phase — see below.
First drawing → move-in	~12–20 months	The number nobody puts in the quote.

Where the time actually goes

Corrections cycles. The single biggest variable. A clean first submittal with a responsive designer clears in two rounds; a sloppy one generates four. Every round is 2–4 weeks of city review plus 2–4 weeks of your response time. Ask your designer, in writing, how many rounds their last five ADU submittals took in your city.

The applicant’s own clock. Designers get busy. Soils reports take 3–6 weeks to schedule. Title 24 consultants queue. Roughly half of “permit delay” stories we hear are applicant-side delay wearing a city costume. Track both clocks separately.

Pre-approved plans: the honest version. AB 1332’s 30-day site-specific review is real, and cities like Riverside (Dwell Riverside), Salinas, Garden Grove, and Anaheim publish the plan sets. But “site-specific” still means soils, grading, setbacks, utilities, fire access, and foundation — the parts most likely to generate corrections. The 30 days cover the unchanged plan details, not the site. Expect the program to save you 4–8 weeks of design and one plan-check round, not to teleport you to issuance.

The utility hookup. Finished ADU, no meter, no power — and waits of 9–12 months documented in legislative testimony. SB 1196 (effective Jan 1, 2027) orders the CPUC to set hard hookup deadlines and lets applicants file the hookup request alongside the building permit. Until then, start the utility conversation during design, not after final inspection. It is the longest phase with the least visibility, and it starts the day you first call, not the day you finish building.

How to protect your schedule

Submit complete. The 15-day completeness clock only helps if your submittal survives it. Use the city’s checklist literally, item by item.
Answer corrections in one pass. Batch every redline into a single resubmittal. Drip-feeding answers restarts rounds.
Get the designer’s round history in writing before you hire them.
File utilities early. Parallel-track the hookup request with plan check, not after final inspection.
Calendar the 60 days. Note the date your application was deemed complete. A polite “day 45” check-in citing the statute moves files.

Disclaimer

Timeline guide, not legal advice. Statutory clocks are statewide; implementation varies by city. Construction durations depend on scope, site, and market conditions. Always confirm current submittal requirements with your city’s building department.

Permit time and permit cost are two different lines. Pair this timeline with the soft-cost breakdown and the full 800 sq ft model.