File for an ADU Permit in Los Angeles With the Right Office

If you’re building an accessory dwelling unit in Los Angeles, you’ll either file with the City through LADBS or with LA County through Regional Planning and Building & Safety, depending on where your property sits. California law gives a complete application a 60-day ministerial review, so your first move today is confirming your jurisdiction and either starting your EPIC-LA submission or downloading a Standard ADU Plan.

TL;DR:

• Unincorporated county projects may need Regional Planning clearance before County Building & Safety accepts construction plans, so verify parcels near city boundaries.
• County standard plans can shorten design review, but applicants still need a measured site plan with accurate utilities, easements, and setbacks.
• The 60 day review period starts only after completeness and fee payment; County site plan review costs $1,025 to $1,252, excluding building permit fees.
• Applicants must track outside agency signoffs themselves; missing Fire or Public Works responses can delay building clearance even after planning approval.
• Before work begins, secure the issued permit, confirm whether a preconstruction meeting is required, and schedule inspections through final approval.

Who issues ADU permits in Los Angeles: city vs county

Before you draw a single line on a site plan, figure out who actually reviews it. Properties inside the City of Los Angeles go through LADBS, while homes in unincorporated LA County fall under the Department of Regional Planning for land use questions and then County Building & Safety for the construction permit itself. Mixing this up wastes weeks, because each office has its own forms, fee schedules, and review software.

A few practical ways to sort this out before you file anything:

• Use your city’s or the county’s parcel lookup tool to confirm whether your address sits in an incorporated city or unincorporated territory.
• Call the planning counter directly if your address sits near a city boundary, since boundary lines can split a block.
• Ask whether your project needs a land use clearance from Regional Planning before Building & Safety will accept your building plans.

Starting with the correct office matters because LA County’s own guidance recommends securing Regional Planning approval before applying to Building & Safety. Submit to the wrong agency first and you’ll likely redo your plan set, trigger duplicate referrals, and lose real time on your 60-day clock.

Standard ADU plans speed up permitting

One of the fastest paths through the system is LA County’s Standard ADU Plans Program, which publishes pre-approved plan sets you can adapt to your lot instead of designing from scratch. The County Catalog includes options such as Standard ADU Plan A and Plan B, larger options roughly around the same size, and Plan C, a more compact option, each already vetted against code.

Using one looks like this:

• Download the plan set that fits your square footage goal from the County Catalog.
• Insert your own site-specific site plan showing property lines, setbacks, and existing structures.
• Fill out the spec sheet on the first page of the plan set with your parcel details.
• Indicate in EPIC-LA that you’re submitting under the Standard ADU Plans Program.

A pre-approved plan shortens design review, but it does not remove the need for accurate site information. Reviewers still check your utility locations, easements, and setback measurements against your actual lot, so a generic plan paired with sloppy site data still gets kicked back.

Pro Tip: Most rejections on standard plans happen because homeowners copy the sample site plan dimensions instead of surveying their own lot, so measure twice before you submit.

Step-by-step application checklist for EPIC-LA

Both Regional Planning and Building & Safety accept submissions through EPIC-LA, and the sequence matters as much as the documents themselves.

1. Assemble your full plan set: site plan, floor plans, elevations, structural calculations, and Title 24 energy compliance documents.
2. Complete the DRP “Base Application - Permits & Review” in EPIC-LA and indicate if you’re using a standard plan.
3. Upload every required attachment in one pass, since EPIC-LA will not accept an incomplete package.
4. Wait for a planner to be assigned, who then checks your submittal for completeness before invoicing fees.
5. Pay the invoice promptly, since plan check review doesn’t begin until fees are paid.

Reviewers look for internal consistency between your site plan and your floor plans, correct scale and dimensions, and matching Title 24 calculations. Most early rejections trace back to missing signatures, mismatched square footage between documents, or an incomplete Land Use Checklist.

Timeline and fees: what to budget for

A complete ADU application gets a decision within 60 days under state law, and that clock applies once your submittal is deemed complete, not the day you upload it. County guidance confirms the 60-day review runs from the date you pay your plan check fees, which is why paying your invoice quickly matters more than people expect.

Sample ministerial site plan review fees in LA County fall in the range of $1,025 to $1,252, separate from building permit fees charged later by Building & Safety. Once approved, your planning clearance stays valid for 2 years, with a one-time 1-year extension available, so don’t let an approval sit unused while you line up financing or a contractor.

Documents that trip up most ADU applications

Plan check reviewers expect a specific set of documents, and missing even one piece restarts your wait.

• A complete site plan showing setbacks, centerline street measurements, existing structures, and any protected oak trees.
• Title 24 energy compliance documentation matching your actual floor plan, not a template.
• Utility location details, including septic or well information where no sewer connection exists.
• Responses to any agency referral, such as Fire or Public Works, before your file can move forward.

The most common mistake homeowners make is treating agency referrals as the county’s job to chase. LA County’s guide notes that planning approval alone doesn’t finish building clearance, since you still need to track outside agency sign-offs yourself.

Pro Tip: Call the referral agency directly a week after submission instead of waiting for a letter, since a short phone call often resolves a stalled referral faster than another round of paperwork.

From approval to permit: inspections and issuance

Once your plans clear review, you still need to convert that approval into an issued permit before any work starts. For City projects, LADBS offers ePlanLA and ePermit Ready To Issue options, letting qualifying license holders pull permits online rather than visiting a counter.

• Complete your Agency Verification Sheet, confirming every referral agency has signed off.
• Check whether your project requires a mandatory pre-construction meeting tied to specific standard notes on your plan set.
• Pull your permit either online through RTI, when your license type qualifies, or in person at the counter.
• Schedule inspections at each construction milestone, finishing with a final inspection before occupancy.

Skipping a required pre-construction meeting can stall your first inspection, so confirm that requirement before crews show up on site.

Ernie M’s practitioner tips for smoother plan checks

After years coordinating HVAC scopes alongside permit submittals, I’ve found that mechanical system details cause more plan-check corrections than almost anything else on an ADU project. I put together three HVAC rules for ADUs versus home additions because the ductwork, equipment sizing, and Title 24 math genuinely work differently for a detached unit than for an addition tied into your existing system.

Include your mechanical layout and your licensed contractor’s contact information on the submittal itself, not as an afterthought added after a correction letter.

When your plan set already shows where the condenser sits, how ducts route through the ceiling, and which contractor is licensed to install it, reviewers have fewer questions and fewer reasons to send your file back. We can walk your site, review your mechanical scope against Title 24, and help you sequence agency referrals before they become delays.

What homeowners get wrong about ADU permitting

Most people treat ADU permitting as a paperwork problem to survive, when it’s really a sequencing problem to manage. The homeowners who move fastest aren’t the ones with the fanciest architect. They’re the ones who confirm jurisdiction on day one, choose a standard plan when their lot allows it, and pay their plan check invoice the same day it arrives.

The conventional advice tells you to “hire a good designer and let them handle it,” which undersells how much of the delay sits outside design entirely: unanswered agency referrals, mismatched Title 24 paperwork, and mechanical details bolted on late. If I could change one habit among Los Angeles homeowners, it would be this: treat your HVAC and electrical scope as part of your plan set from the first submission, not a detail to resolve after a correction letter arrives. That single shift saves more weeks than any architect’s drawing style.

Prioritize jurisdiction confirmation first, a standard plan second if your lot qualifies, and mechanical coordination third, before you ever touch a shovel.

— Ernie M

How Upright Construction & HVAC supports your ADU build

We assist with key parts of an ADU project that can affect permit processing, such as mechanical system design, Title 24 coordination, and licensed trade documentation that reviewers look for on your plan set from the start.

• ADU construction services covering site assessment through framing and finish work.
• HVAC design and integration scaled appropriately for your unit’s square footage.
• Permit coordination aimed at maintaining consistency between your mechanical scope and your plan set.
• Mechanical systems prepared for inspection to help minimize callback visits.

If you’re ready to move past the planning stage, visit our ADU construction page to talk through your site and your timeline with our team. For interior fit-out details like closet systems and interior doors during your ADU build, One Day Doors & Closets serves the Los Angeles area with fast, custom installation.

This article is general information, not a substitute for advice from a qualified lawyer. Consult a qualified legal professional about your own circumstances before acting on anything here.

FAQ

Is there a $40,000 ADU grant available in California?

California’s ADU grant programs have changed over time, and current availability depends on the specific program and funding cycle at the time you apply. Check the HCD ADU Handbook for the latest state-level guidance before assuming a specific grant amount applies to your project.

How much does it cost to get an ADU permit in Los Angeles?

Ministerial site plan review fees in LA County typically run $1,025 to $1,252, separate from building permit fees charged once plan check begins. Your total cost depends on your jurisdiction, plan size, and whether you use a pre-approved standard plan.

What are the requirements for an ADU in Los Angeles?

Your ADU must meet objective development standards covering setbacks, height, lot coverage, and parking, and a complete application meeting those standards qualifies for ministerial approval rather than discretionary review. Exact requirements depend on whether your property sits in the City of Los Angeles or unincorporated LA County.

How long does it take to get an ADU permit in Los Angeles?

State law requires a decision on a complete application within 60 days, with that clock starting once your submittal is deemed complete and fees are paid. Using a Standard ADU Plan from the County Catalog can help your application reach completeness faster.

Sources

• Standard ADU Plans Program - County Catalog
• Plan Review & Permitting | LADBS
• ADU Handbook | California Department of Housing and Community Development

Recommended

• Homeowners: Ernie M’s 3 HVAC Rules For ADU Vs Home Addition