The LA ADU Permit Process, Step by Step (2026 Guide)

If you own a house in the City of Los Angeles, the state has made it about as easy as it's ever been to add an accessory dwelling unit (ADU). "Easier" still isn't "easy," though. Most ADU delays have nothing to do with construction. They come from incomplete plans, surprises on the site, and corrections that bounce back and forth with plan check.

This guide covers the permit path for a detached or attached ADU, or a garage conversion, in the City of LA, which is permitted by the Los Angeles Department of Building and Safety (LADBS). If your lot is in another city, such as Pasadena, Glendale, Santa Monica or Culver City, or in unincorporated LA County, the steps are similar but the agency and the forms are different.

Step 1: Confirm what your lot allows

Start with the City's free parcel tool, ZIMAS. Enter your address and note:

• Zone (R1, RS, R2 and so on) and any specific plan, HPOZ or overlay. Historic Preservation Overlay Zones add a design review step.
• Hillside area, Very High Fire Hazard Severity Zone, or methane zone flags. Each can add requirements such as fire sprinklers, a methane mitigation system or a soils report.
• Easements and lot dimensions, which matter for setbacks.

California's ADU law, now in Government Code sections 66310 to 66342, sets limits on what a city can require. Generally, cities must allow an ADU with 4-foot side and rear setbacks, and they can't require replacement parking when a garage is converted or demolished for an ADU. The state's HCD ADU Handbook is the best plain-language summary of those rules. Read the current version, because the law has been amended almost every year.

Step 2: Choose your plan route

You have three realistic options:

1. Custom plans from an architect or designer. This is the most flexible option and the slowest.
2. The City's Standard Plan Program. LA has a library of pre-approved ADU designs from private architects, plus a free City-owned plan (YOU-ADU). Many private plans have expired, so check the list for ones currently marked Approved. The building design is already reviewed, so plan check focuses mostly on the site: placement, utilities and the foundation for your soil.
3. Prefab or manufactured units. These still need a site permit, a foundation and utility connections.

Whichever you pick, you'll typically need a site plan, floor plans, elevations, structural calculations, Title 24 energy compliance forms and, depending on the lot, a soils or geology report.

Step 3: Submit to LADBS plan check

Applications are submitted through LADBS's online services. Plan check reviews building and structural code, and the plans are routed to other agencies as needed. Common clearances include:

• LA Sanitation for the sewer connection or a sewer capacity check
• LADWP for electrical service and water meter questions
• LAFD for fire access and sprinkler requirements in some zones
• Urban Forestry, if protected trees or street trees are affected

Under state law, the agency must tell you within 15 business days whether your application is complete. Once a complete ADU application is submitted, the local agency must approve or deny it within 60 days, or the application is deemed approved (Gov. Code §66317). The clock runs on a complete application, so missing documents or a correction cycle can effectively restart it. The fastest projects answer correction sheets within days, not weeks.

Step 4: Fees

Expect plan check and permit fees from LADBS, plus possible school district fees and utility charges. State law exempts ADUs with 750 square feet or less of interior livable space from impact fees. Above that size, impact fees have to be proportional to the main house (Gov. Code §66311.5, formerly §66324). School districts can charge fees on ADUs over 500 square feet, but not on smaller ones (HCD ADU Handbook). Check the current fee schedule with LADBS and the school district for your exact number rather than relying on a ballpark.

Step 5: Permit issued, now hire the trades

Once the permit is issued, the plans are stamped and you can build. This is where many owners discover that "one ADU" is really 10 to 15 different trades. A typical detached ADU needs:

• Grading and concrete for the foundation and slab
• Framing and carpentry
• Roofing
• Electrical (often a service upgrade or a new meter)
• Plumbing and the sewer lateral
• HVAC, usually a heat pump mini-split
• Insulation, drywall, stucco, paint and flooring

You can hire a general contractor to run all of it, or, if you're experienced, bid it out trade by trade. Either way, verify every contractor's license with the CSLB before signing, and confirm workers' comp coverage for anyone with employees. Our CSLB license check guide walks through it.

Step 6: Inspections

LADBS inspects at set stages, usually foundation, framing, rough mechanical, electrical and plumbing, insulation, drywall nailing, and final. Some designs also need a deputy inspector for special inspections such as shear wall nailing, epoxy anchors or structural welding. The plans will list them. Schedule inspections ahead and keep the approved plan set on site; an inspector can't sign off on work they can't compare to the plans.

Step 7: Final and Certificate of Occupancy

After the final inspection passes, LADBS issues a Certificate of Occupancy for the new unit. Utilities can be finalized at that point, and the ADU can be legally occupied or rented. A new ADU can trigger a property tax reassessment, but only for the added value; the existing house keeps its assessed base.

Where ADU projects usually stall

• Survey and setback surprises. Order a survey early on tight lots.
• Electrical service capacity. Main-panel and service upgrades with LADWP can take time, so ask early.
• Sewer depth and location. If the ADU sits lower than the street sewer, you may need a pump. Find out before you finalize the site plan.
• Slow correction responses. The 60-day clock only helps if you answer quickly.

Getting bids on your ADU

Once you have plans, comparable bids are easier: every contractor prices the same scope. On Bidroom you can post your project by trade or as a whole, and local contractors send a price and a timeline. Contractors can see what ADU work is open right now on the LA jobs board.

For a broader overview of ADU types and state rules, see our California ADU guide.

This article is general information, not legal advice. ADU rules change often; confirm current requirements with LADBS and HCD before you design or build.