Expect several months from your first site assessment to Certificate of Occupancy for an accessory dwelling unit in Los Angeles. Plan check runs on a 15-business-day completeness review followed by a 60-day approval clock, and homeowners with older unpermitted units may qualify for a separate amnesty path that moves faster.
TL;DR:
- Most ADU permits in Los Angeles take between six to fourteen months from feasibility to occupancy, with delays often caused by incomplete submissions or utility issues.
- Combining design, engineering, and construction management through a single firm can reduce timelines by avoiding costly reworks and coordinating early with city agencies.
- The 15-business-day completeness review resets if any documents are missing, and the 60-day approval clock begins only after the application is deemed complete.
- Homeowners with unpermitted units built before 2020 may qualify for the AB 2533 streamlined permitting path, which can exempt them from impact fees and speed up approval.
- Utility upgrades, fire safety requirements, and phased design decisions can extend project timelines and add significant costs, so proactive planning is essential.
Step by step: the ADU timeline from feasibility to move-in
Every ADU project in Los Angeles moves through the same general phases, though the pace inside each one depends heavily on your lot, your design choices, and how quickly you respond to agency requests.
- Feasibility and site assessment. Confirming lot size, setbacks, zoning overlays, and utility capacity typically takes one to three weeks and determines whether a detached, attached, or garage-conversion ADU fits your property.
- Design and permit-ready drawings. Architectural drafting, structural engineering, and Title 24 energy compliance usually take two to eight weeks, depending on whether you use a custom design or a pre-approved standard plan.
- Plan check submission. Once drawings go into ePlanLA or an LADBS counter, the clock for completeness and approval starts, and correction cycles are the single biggest variable in how long this stage runs.
- Construction. Detached units and garage conversions commonly take four to eight months to build, while junior ADUs carved from existing floor space can finish faster since they skip foundation work.
- Final inspection and Certificate of Occupancy. Scheduling the last inspection and closing out utility clearances typically adds one to three weeks after construction wraps.
Pro Tip: Order your structural engineering and Title 24 report in parallel with architectural drafting instead of after it, since sequencing them back to back can add two to three weeks for no reason.
How the 15-day and 60-day permit clocks actually work
The 15-business-day completeness review begins once you submit your application package, and LADBS uses that window to decide whether your drawings and supporting documents are sufficient to review. If anything is missing, the clock resets once you resubmit a corrected package rather than continuing to run.
The 60-day approval clock starts only after your application is deemed complete, and if the city does not approve or deny within that period, state law allows the project to be treated as “deemed approved” under the framework ZA Memo 143 implements.
- Combined permits (plumbing, electrical, mechanical, and building reviewed together) can extend the practical timeline even when each individual clock is respected.
- Discretionary reviews, which are rare for standard ADUs but common on hillside or historic-overlay lots, sit outside the ministerial 60-day rule entirely.
- Paying plan-check fees promptly and answering correction letters within days, not weeks, keeps your application moving through both clocks without unnecessary resets.
AB 2533 amnesty for older unpermitted ADUs
Homeowners with a unit built before January 1, 2020 that already meets the state’s ADU or JADU definition may qualify for the streamlined path described in LADBS Information Bulletin P/BC 2026-161. This program is built for units that were never permitted but have functioned as housing for years.
- Acceptable proof includes RSO rent registration, contractor invoices, utility bills, signed leases, or MLS listing records.
- An optional third-party inspection through LASC can substitute for some standard plan-check steps.
- Submittals go through ePlanLA alongside the minimum documentation list in the bulletin.
Homeowners who qualify under AB 2533 are exempt from impact fees unless the project requires utility infrastructure upgrades, according to the AB 2533 bulletin, which can shave weeks off the fee-resolution stage that normally precedes permit issuance.
Construction milestones, inspections, and how to avoid re-inspections
Once permits are in hand, construction follows a fairly predictable sequence of inspections, and each one needs to pass before the next trade can start.
- Foundation and underground utilities, inspected before any backfill or slab pour.
- Framing, inspected after rough structural work is complete but before walls are closed up.
- Mechanical, electrical, and plumbing rough-in, inspected before insulation goes in.
- Insulation and Title 24 HERS verification, confirming the energy compliance package matches what was permitted.
- Finishes and final inspection, which also triggers Certificate of Occupancy review.
Inspections are scheduled through LADBS’s online system, and utility or agency clearances from LADWP, the fire department, and sewer connections often sit on the critical path to closing out the permit, as LADBS’s ADU guidance notes.
Pro Tip: Keep permitted drawings, approved corrections, and manufacturer spec sheets on-site at every inspection, since missing paperwork is one of the most common reasons an otherwise ready project fails its first inspection attempt.
Why ADU projects stall, and how to keep yours moving
Most delays trace back to a handful of avoidable problems rather than bad luck.
- Incomplete submittals restart the completeness clock, so a single missing structural calculation can cost another 15 business days.
- Skipping early utility coordination with LADWP or SoCalGas often surfaces capacity issues mid-construction instead of during design, when they are cheaper to fix.
- Standard or pre-approved plans speed up plan check significantly, but hillside lots, fire hazard severity zones, and historic overlays still trigger extended review even with a standard design.
- A contract that spells out schedule milestones, response times for corrections, and clear deliverables gives you leverage when a project partner falls behind.
Fees, upgrades, and what they do to your schedule
Plan-check fees are typically due at submission, while permit issuance fees come due once the application is approved, and missing either payment window pauses the process.
- Sewer capacity upgrades or required fire sprinklers can add both cost and weeks, since they often require separate review from other departments.
- Budgeting contingency time, not just contingency dollars, for utility coordination keeps a tight schedule from collapsing over a single unresolved clearance.
- Phasing design decisions, like finalizing utility connections before finishes, reduces the odds of a late-stage scope change pushing back your final inspection.
More detail on how these fees interact with plan check timing is covered in our guide to ADU permit costs in Los Angeles.
Where professional coordination actually saves time
The biggest schedule risk in most ADU projects is not the LADBS clock itself, it is the handoffs between designer, engineer, and contractor. Bringing structural engineering and Title 24 review in early, rather than after drafting is finished, avoids rework that otherwise shows up as a correction cycle weeks later.
, Uni Construction
How Uni Construction fits into your permit timeline
Homeowners trying to hit the shorter end of that 6 to 14 month range benefit from having design, engineering, and construction coordinated under one roof instead of juggling separate vendors who do not talk to each other.
A design-build firm can offer architectural design, structural engineering, and permit-ready drawings built around LADBS submittal requirements, along with construction management that carries a project through final inspection.
- Ask a feasibility call whether your lot qualifies for pre-approved standard plans or needs custom design.
- Ask how design and structural engineering are sequenced to avoid plan-check corrections.
- Ask who manages utility and fire clearance coordination during construction.
See current project examples and start a feasibility conversation on the Detached ADU, Attached ADU, and Garage Conversion services page.
Sources
FAQ
Plan check itself generally moves through a 15-business-day completeness review followed by a 60-day approval window once the application is complete, per ZA Memo 143. Including design and construction, most homeowners should plan for a 6 to 14 month total project timeline.
AB 2533 lets homeowners with an unpermitted ADU built before January 1, 2020 pursue a streamlined permitting path through LADBS, using documents like rent registration records, utility bills, or leases as proof of the unit’s age. Qualifying homeowners can be exempt from impact fees unless utility infrastructure upgrades are required.
The most significant 2026 change in Los Angeles is the AB 2533 streamlined permitting bulletin, which gives older unpermitted units a documented path to legal status outside standard plan check. Standard ADU ordinance rules, including ministerial approval when objective standards are met, continue to apply alongside it.
Published pricing varies by scope, finishes, and site conditions, and no single statewide figure applies to every project. A feasibility assessment is the most reliable way to get a cost range specific to your lot and design.
