How long does ADU plan check take at LADBS? What the Valley's 2025 permits show

How long does it really take to get an ADU permit from LADBS in the Valley?

It usually takes three to nine months for a new detached ADU and one to four months for a conversion. We pulled every original ADU building permit that LADBS issued in 2025 in the 35 City of LA ZIP codes in the Valley and counted the calendar days from the submitted date to the issue date ¹⁵. Here is what came back:

• New detached ADU (910 permits): median 142 days. The middle half took 79 to 268 days. 17% were issued within 60 days, and 17% took more than a year ¹⁵.
• Attached ADU built as an addition (588 permits): median 97 days, middle half 51 to 188 ¹⁵.
• Conversion of an existing building, such as a garage (464 permits): median 66 days, middle half 31 to 129. 45% were issued within 60 days ¹⁵.

The neighborhood matters less than you might think. New detached ADUs had a median of 136 days in Reseda 91335, 135.5 in Granada Hills 91344 and 157 in Pacoima 91331 ¹⁵. The lot matters more. On the 59 new detached ADUs in the dataset that sit on hillside lots, the median was 210 days ¹⁵.

These numbers count the whole stretch, not just the time a plan checker has your plans on the desk. The dataset cannot separate the city's review time from the time an owner's designer spends answering corrections. For how many permits each Valley ZIP issues, see ADU permits in the San Fernando Valley by ZIP.

Will my ADU go through regular plan check or the faster counter line?

It depends on what you are building. LADBS runs a regular plan check for larger projects and an Expanded Counter Plan Check (ECPC) for modest ones, where permits can be issued over the counter and plans are assigned within a few days of submittal ⁸. LADBS's qualification bulletin lists a conversion of an existing building, a one-story addition that creates an ADU, and a new one-story detached ADU that is not under the Baseline Hillside Ordinance or the hillside rules as projects that generally qualify for ECPC ⁹.

The gap between the two lines is large in the 2025 Valley data. New detached ADUs in regular plan check took a median 160 days, with the middle half at 100 to 311. In ECPC the median was 102.5 days, with the middle half at 50 to 202 ¹⁵. A two-story ADU or a hillside lot generally means regular plan check.

Regular plan check also has a paid shortcut. LADBS says plans are reviewed and returned within weeks depending on workload, and that paying 50% more of the plan check fee gets the review expedited ⁷. That speeds the city's review. It does not speed your corrections or the other departments.

What happens when plan check sends back corrections?

You get a correction sheet, your designer answers every item, and the plan checker verifies the answers before the permit can issue. The LADBS ADU correction sheet asks for a written response or a reference to the revised detail for every correction, with the location of each revision identified ¹⁰. On electronic plan check, the revisions and responses are uploaded through the ePlanLA portal. On paper plans, verification is in person, by appointment only ¹¹.

Two things on that sheet affect your calendar:

1. Corrections are verified at the same office where the plans were checked ¹¹. If the Van Nuys office checked your plans, the answers go back to Van Nuys.
2. The permit application expires 18 months from the plan check submittal date ¹⁰. A file that sits while you rethink the design or wait on financing is still running out that clock.

Each round costs time on both sides. Most of what stretches the 66-day and 142-day medians above into a year is more rounds, not one slow reviewer.

Why isn't the permit issued as soon as plan check approves the plans?

Because other departments have to sign off first. The correction sheet tells you to obtain all clearances listed on the Clearance Summary Worksheet and warns that it can take months for some departments to review the project ¹². The final plans may need stamps from City Planning, the Fire Department, the Green Building division and Sanitation ¹³.

Some clearances depend on the lot:

• Fire access. New construction with a project value of $50,000 or more needs a fire lane clearance from the Fire Department's hydrants and access unit when any part of the building is more than 150 feet from the edge of an improved street or approved fire lane ¹³. See ADU rules in the Granada Hills fire zone.
• DWP easements. Any work within 10 feet of a DWP easement, including a conversion, needs written DWP approval ¹³.
• Sewer and water. Sewer capacity and connection questions are covered in the sewer main guide, and a new water service has its own long timeline, covered in the LADWP water meter guide.

Start these the week you submit, not after the plan checker is done.

Doesn't state law say the city has to approve my ADU in 60 days?

It says the city has to approve or deny a completed application within 60 days, which is narrower than it sounds. Under Government Code section 66317, the city must decide whether your ADU application is complete and tell you in writing within 15 business days, with a list of anything missing ¹. Once the application is complete, the city must approve or deny it within 60 days if there is already a house on the lot ². If it does neither, the application is deemed approved ³. HCD notes that this limit used to be 120 days ⁶.

Read the conditions closely:

• If the city denies the application, it must give you a full set of written comments listing what is deficient and how to fix it within that same period ⁴.
• If you ask for a delay, the 60 days stop running for as long as the delay lasts ³.
• If the ADU is filed together with a new house on the lot, the city may hold the ADU until it decides on the house ⁵.

The clock is about the city's decision on a complete application. It does not count the weeks your designer takes on corrections, and it does not cover the other departments' clearances. That is why a 142-day median can sit next to a 60-day rule. Keep your own record of the submittal date, any completeness notice, each correction sheet and each resubmittal. If you think the clock has run, those dates are what you will need.

What can I do to shorten my plan check?

Pick the simplest building your lot allows, submit a complete set, and answer corrections fast. Some specific steps:

• Use an approved standard plan if one fits. LADBS says standard plans shorten the time needed to review plans through plan check and get permits issued more quickly, because the plan is pre-approved and the review checks that it fits your property ¹⁴. See LA standard ADU plans.
• Convert before you build new, if the building is sound. Conversions had the shortest median in 2025, at 66 days ¹⁵. Check first that the garage was permitted with the garage permit lookup.
• Stay one story off the hillside if you can. That keeps a new detached ADU eligible for the counter line ⁹.
• Start the clearances the week you submit ¹².
• Never let the file sit. The 18-month expiration runs from the submittal date ¹⁰.

Most of the slow files in the data are slow because of something on the lot that showed up after the plans were drawn: a hillside, an easement, a fire lane, a sewer line. Finding those before design starts is the kind of thing a lot check settles.

Quick answers

Sources

1. Government Code section 66317(a)(2): completeness determination, State of California (text via California.Public.Law). Facts checked 2026-10-09
2. Government Code section 66317(a)(3): 60-day approval or denial, State of California (text via California.Public.Law). Facts checked 2026-10-09
3. Government Code section 66317(a)(3): tolling and deemed approval, State of California (text via California.Public.Law). Facts checked 2026-10-09
4. Government Code section 66317(b): comments on denial, State of California (text via California.Public.Law). Facts checked 2026-10-09
5. Government Code section 66317(a)(3): ADU filed with a new dwelling, State of California (text via California.Public.Law). Facts checked 2026-10-09
6. Accessory Dwelling Unit Handbook, California Department of Housing and Community Development. Facts checked 2026-10-09
7. Regular Plan Check, LADBS. Facts checked 2026-10-09
8. Expanded Counter Plan Check, LADBS. Facts checked 2026-10-09
9. Information Bulletin P/GI 2026-011, Qualification Criteria for Counter Plan Check (CPC), Expanded Counter Plan Check (ECPC) & Regular Plan Check (RPC), LADBS. Facts checked 2026-10-09
10. ADU, JADU, Movable Tiny House Correction Sheet, PC/STR/Corr.Lst.20A (rev. 10/01/2025), LADBS. Facts checked 2026-10-09
11. ADU, JADU, Movable Tiny House Correction Sheet: verification of corrections, LADBS. Facts checked 2026-10-09
12. ADU, JADU, Movable Tiny House Correction Sheet: clearances, LADBS. Facts checked 2026-10-09
13. ADU, JADU, Movable Tiny House Correction Sheet: fire lane, DWP easement and plan stamps, LADBS. Facts checked 2026-10-09
14. Accessory Dwelling Unit (ADU): ADU Approved Standard Plans Program, LADBS. Facts checked 2026-10-09
15. Building and Safety - Building Permits Submitted from 2020 to Present (N), dataset gwh9-jnip (Greenlight query, Valley ADU permits issued in 2025), City of Los Angeles Open Data / LADBS. Facts checked 2026-10-09

Greenlight is not a contractor, architect or engineer, and this is not legal advice. Rules change; every fact here shows the date we last checked it.