Solid ADUADU permits and inspections in Los Angeles, explained step by step
Every legal ADU in Los Angeles goes through the same gauntlet: LADBS plan check, a building permit, and a series of inspections that ends with a Certificate of Occupancy. Here is what actually happens at each step, and how Solid ADU guides you through all of it, with one point of contact from first idea to final inspection.
Why the permit process decides your ADU timeline
California's state ADU law allows an accessory dwelling unit on most residential lots that have an existing or proposed home. In the city of Los Angeles, the Department of Building and Safety (LADBS) is the agency that reviews your plans, issues the permit and sends the inspectors. No matter how fast a crew can build, your ADU only moves as fast as its permits and sign-offs do.
Skipping the process is not a shortcut. An unpermitted unit can trigger code enforcement, complicate a sale or refinance, and cannot be legally rented as a dwelling. Doing it right from day one is almost always cheaper than fixing it later, especially for garage conversions, where unpermitted work is common in older LA neighborhoods.
The process below is the same whether you build a garage conversion, a detached backyard unit or an attached ADU. What changes is which inspections apply and how heavy each one is.
Step 1: plan check, from drawings to an issued permit
It starts with a complete set of plans: floor plan, elevations, structural details, and the Title 24 energy calculations. Those drawings go to LADBS for plan check, the city's review of whether the design meets building, zoning, electrical, plumbing and mechanical codes. Submissions run through the city's electronic plan check system, and depending on your lot other clearances can apply, for example from City Planning or, in hillside and fire districts, the Fire Department.
State ADU law puts a clock on this: the city must approve or deny a complete ADU application within 60 days. In practice, plan check usually comes back with corrections, comments the designer has to answer before approval. Vague drawings mean more correction rounds, and every round costs weeks. This is why your contractor's team draws your ADU plans to LADBS expectations and answers corrections promptly, and why we track every correction round for you instead of letting it sit in an inbox.
Once plan check is approved and the permit fees are paid, LADBS issues your building permit. Now, and only now, construction can legally begin.
Step 2: the inspection card, your ADU's official checklist
With the permit comes an Inspection Record, the card that lists every inspection your project must pass, in order. At each stage an LADBS inspector visits the site, checks the work against the approved plans, and signs the card. The approved plans and the card must be available on site at every visit, and inspections are requested through the LADBS online system or by calling 311.
One rule governs the whole card, and it is printed on it: work may not be covered or concealed until it has been inspected and signed off. Concrete hides rebar, drywall hides wiring, soil hides pipes. If you cover unapproved work, the inspector can require you to open it back up. The sequence below follows the real LADBS card.
- 1
Grading and site preparation
On sloped lots or projects that move soil, a grading inspection comes first. The inspector checks excavation depths, compaction and how the site will drain, because water that runs toward the new foundation causes problems for decades.
Common issue: drainage that sends runoff toward a neighbor or toward the building. Your contractor plans the drainage path before a shovel hits the ground.
- 2
Footings and foundation
Before any concrete is poured, the inspector verifies the trenches, forms and rebar against the approved structural plans: depth, width, steel size and spacing, and the hold-down hardware that ties the future walls to the foundation.
Pouring before this sign-off is the classic expensive mistake, because the only fix is demolition. The contractors in our network never schedule a pour until the card is signed.
- 3
Groundwork: electrical, plumbing and gas piping
Everything that will be buried or cast into the slab is inspected while it is still visible: underground electrical conduit, drain and waste lines, water lines and gas piping. Drain lines are typically tested under water or air pressure so leaks show up now, not under your finished floor.
The inspector also checks slopes on drain lines, because a drain that does not fall correctly will clog for the life of the building.
- 4
Rough framing, electrical, plumbing and HVAC
With the structure framed and the roof on, the rough inspections cover everything inside the open walls: framing connections, shear walls and hardware, electrical boxes and wire runs, supply and drain lines, and the ducting and refrigerant lines for heating and cooling.
This is the most detailed stop on the card. Typical corrections are missing nailing on shear panels, overdrilled studs and missing fire blocking. Your contractor's team pre-walks the building against the plans before the inspector does.
- 5
Insulation and energy inspection
California's Title 24 energy code sets minimum insulation values for walls, ceilings and floors. The inspector confirms the installed insulation matches the energy calculations that were approved with your plans, with no gaps or compressed batts.
Skipping ahead here is tempting because insulation is quick to cover up. It is also exactly why the card says not to.
- 6
Lathing and drywall nailing
Before plaster or joint compound goes on, the inspector checks how the drywall and exterior lath are fastened: nail and screw type, spacing and edge distances. On walls that need a fire-rated assembly, such as a wall close to a property line, the correct board type is verified too.
It looks like a formality. It is not: fastening is what makes a wall perform in a fire or an earthquake.
- 7
Work outside the building
The card has a line for site work outside the unit itself: the sewer connection, the electrical service and panel, gas meter location, site drainage and any required exterior stairs and landings.
For ADUs this often includes the trench that connects your new unit to the existing utilities, which is inspected open, just like the groundwork.
- 8
Final inspections per trade
Near the end, each discipline gets its own final: electrical (fixtures, outlets, smoke and carbon monoxide alarms, panel labeling), plumbing (fixtures, water heater, gas test), and mechanical (heating and cooling in working order).
The building final then looks at the finished whole: egress windows, guardrails, weatherproofing, address numbers and everything in between.
- 9
Project Final and Certificate of Occupancy
When every line on the card is signed, the project final closes out the permit and LADBS issues the Certificate of Occupancy for your new dwelling unit. That document is what makes your ADU a legal home you can rent out.
We stay involved until that certificate is in your hands. That is our definition of done.
Rather never think about inspection cards again?
That is the point of working with us. You get one point of contact, and a vetted licensed contractor whose team handles plans, permits, construction and every LADBS inspection. Free feasibility check, response within 24 hours.
What makes garage conversion inspections different
A garage conversion starts from an existing structure, so the inspection story shifts. There is usually little or no grading, but the existing slab and footings get real attention: garage slabs were poured for parking cars, not for living space, and where new plumbing runs under the slab it is cut open, trenched and inspected before it is closed again.
The old garage door opening becomes a framed, insulated wall, and the inspector checks how that new wall is tied to the existing structure. Walls that sit close to a property line may need a fire-rated assembly, and the whole unit has to meet today's energy code even though the shell is decades old. Expect the rough and insulation inspections to be just as thorough as on a new build.
This is our home turf. Garage conversions are the core of what we guide, and we know what LADBS inspectors look for in LA's older garage stock: undersized framing, unpermitted old wiring, slabs without moisture barriers. The contractors we match you with deal with those realities in the plans, not as surprises halfway through your build.
We walk every inspection with you
You never have to call 311, chase an inspector's time window or decode a correction notice. Your contractor's team requests every inspection at the right point in the schedule and walks the site beforehand to catch issues while they are cheap to fix, and we stay involved through every visit so you always know where your project stands. If a correction comes up on the contractor's work, they resolve it and book the re-inspection.
All of it falls under one clear fixed proposal from your licensed contractor, covering your ADU from plans to Certificate of Occupancy, with Solid ADU as your single point of contact. Curious how the whole journey looks? See how we work, or start with a free feasibility check.
Frequently asked questions about ADU permits and inspections
Do I need a permit for a garage conversion in Los Angeles?
Yes. Turning a garage into living space changes its use, so LADBS requires a building permit plus the electrical, plumbing and mechanical permits that go with it. The good news: under California ADU law a conversion of an existing garage is allowed on most residential lots, and the existing structure can usually stay where it stands even if it does not meet today's setback rules for new construction. We check your specific lot in a free feasibility check before you commit to anything.
How long does LADBS plan check take for an ADU?
State ADU law requires the city to approve or deny a complete ADU application within 60 days. In practice the total timeline depends on how complete your drawings are and how quickly plan check corrections are answered. Because your contractor's team prepares the plans to LADBS expectations and responds to corrections quickly, that loop stays as short as possible, and we keep an eye on the timeline for you. You get a realistic timeline for your project during the feasibility check.
What happens if an inspection fails?
The inspector leaves a correction notice that lists exactly what needs to change. The work is fixed, a re-inspection is scheduled, and the project moves on. A correction is not a disaster, it is a normal part of construction. Because the licensed contractors in our network build to the approved plans and walk the site before every inspection, corrections are rare and small, and your contractor resolves them at no cost to you when they concern the contractor's own work.
Who schedules the LADBS inspections?
Your contractor's team does. Inspections are requested through the LADBS online system or by calling 311 within Los Angeles, and each one must be requested at the right moment in the build. Your contractor plans them into the construction schedule, makes sure the approved plans and the inspection card are on site, and is present when the inspector arrives. We stay involved and keep you posted at every step.
Can I legalize a garage that was converted without permits?
Often, yes. An unpermitted conversion can usually be brought through the normal permit process: plans are drawn for the existing condition, LADBS reviews them, and inspectors verify the work, which can mean opening up walls to show framing, wiring and plumbing. Every situation is different, so we start with an honest assessment of what it would take before you spend anything.
What is a Certificate of Occupancy and why does it matter?
The Certificate of Occupancy is the city's confirmation that your ADU passed its final inspections and is approved as a legal dwelling unit. It is the document that lets you legally rent the unit out, and it is what lenders, insurers and future buyers ask for. Your project is not finished until you have it, which is why we treat it as the finish line of every ADU project we guide.
Ready for an ADU that passes every inspection?
Call us or leave your number and we will call you back within 24 hours. The feasibility check is free and you decide what happens next.