How long an ADU permit takes in Los Angeles

The clocks the law sets

Since January 1, 2026, state law fixes three deadlines for every city and county in California. These come from the ADU rules file the property report is built from.

Step	Deadline
Is the application complete?	15 business days from submittal for the city to say so in writing, listing what is missing and how to fix it. The same 15 business days apply to each resubmittal. In LA County, no notice within 15 business days means the application is deemed complete.
Decision	60 days from a complete application to approve or deny. If the city misses it, the application is deemed approved.
Appeal	A written appeal of an incompleteness finding or a denial gets a final written decision within 60 business days. LA County: appeal to the Regional Planning Commission within 14 calendar days.
Coastal zone	With a certified local coastal program, the coastal development permit decision is due within 60 days and appeals to the Coastal Commission are removed. Without one, the Commission reviews on a 60-day clock.

Those are the city's deadlines. The time you control, and the time other agencies take, sit on either side of them.

Before the clock starts

The 15 business days begin when you submit, so the weeks before submittal decide how many rounds you go through.

• Design. A pre-approved plan removes most of this step. With a custom design, the architect's drawings, structural calculations and energy calculations all have to be finished before plan check.
• A complete set of plans. LADBS's ADU bulletin says a complete set of plans is required for plan check submittal, with document requirements listed in Information Bulletin P/GI 2026-008. An incomplete set is the most common reason for an incompleteness letter, and each one restarts the 15 business days.
• Records research. For a conversion of a building that was permitted before, LADBS asks for the building's certificate of occupancy and previous permits at the plan check stage, to verify its permitted use.
• The site. A survey if the edges of the property are unclear, a soils report where LADBS asks for one, and the location of the nearest fire hydrant. Every part of the ADU should be within 150 ft of a hydrant along an access path, or LAFD can require sprinklers or other measures.

Plan check at LADBS

With a standard plan, LADBS has already checked the design against the building, residential, green and energy codes. Its page on the program says the use of a standard plan greatly reduces the time required for plan check, and that plans still need final review to address site-specific conditions and clearances before a building permit is issued. Localized soil conditions may require site-specific foundation work.

With a custom design, the full plan check applies. Either way, the plan checker issues clearances that other agencies must sign before the permit is issued. In the county program, the plan check engineer issues a referral sheet and the listed agencies' approvals must be submitted before permit issuance.

After the permit

The permit is the start of construction, and construction time depends on the kind of ADU, the builder's schedule and inspections. ADUCheck does not publish construction durations because they vary too much to source honestly; ask our partners for a schedule with your bid.

Two deadlines matter once the permit is issued. In unincorporated LA County, the permit holder must request an inspection within 12 months of issuance to avoid expiration, and follow-up inspections every 180 days. In the City of Los Angeles, confirm the permit's expiration terms with LADBS when it is issued.

What slows things down

• Incomplete plans. Each resubmittal restarts the 15 business days.
• Hillside streets and very high fire hazard zones. LA City limits detached ADUs in these areas, especially on streets narrower than the city's standard, and requires fire sprinklers in very high fire hazard zones. The report flags both.
• Fire department access. The 150 ft hydrant rule can add a sprinkler system to the scope.
• Historic districts. In an HPOZ, design review may apply to what is visible from the street.
• Unpermitted work. A garage that was already converted without permits can be legalized under AB 2533 if it was built before January 1, 2020, but it needs its own documentation and, for older work, a substandard-building checklist. See the LADBS bulletin.

When the city says no

A denial or an incompleteness finding can be appealed in writing. The final written decision is due within 60 business days. In unincorporated LA County the appeal goes to the Regional Planning Commission within 14 calendar days. If a rule the city applied is stricter than state law, state law wins; HCD reviews local ordinances and publishes findings letters.

A guide is a starting point, not a permit. Confirm the current process with LADBS before you submit.