Unincorporated LA County Permits, Agency by Agency

If your property is in unincorporated Los Angeles County, your building permit is not one approval. Public Works Building and Safety issues it. But it issues only after every agency on its Agency Referral sheet has signed off. That can mean:

• the Fire Department;
• your water company;
• the Sanitation Districts;
• Regional Planning;
• the County’s geology and soils reviewers;
• Public Health;
• your school district;
• the County Library.

Each has its own queue, forms and fees.

The County’s own referral sheet puts it plainly: "Follow-up is your responsibility."

This page walks through every agency you may meet, what each one checks, and where projects lose months. It closes with seven County projects from our own files.

On this page: Is it County? · How a permit moves · The agencies · ADUs and state law · Seven real projects · Where months go · How we run a County project · FAQ

Your mailing address does not tell you. Our own County projects include homes with Pasadena, Calabasas, Malibu, Inglewood, Hawthorne and Whittier mailing addresses. In each case the County handles zoning, plan check and permits, not the city on the envelope.

Unincorporated areas include:

• Altadena, East Los Angeles, Hacienda Heights and Rowland Heights;
• Topanga and the Santa Monica Mountains;
• Acton, Agua Dulce and much of the Antelope Valley;
• dozens of smaller communities.

Two ways to check:

• Public Works service locator. Look up the address at dpw.lacounty.gov/general/servicelocator. It also shows your water company and school district.
• Regional Planning zoning map. It shows the zone and any Community Standards District.

Some cities contract with the County for building plan check. Their projects get a County referral sheet too, but zoning stays with the city.

1. Zoning review by Regional Planning.
   • Most projects need a Regional Planning approval before the building permit can issue. It is filed as a sub-record of your building application in EPIC-LA, the County’s online permit system.
   • Regional Planning checks the zone, setbacks, height, lot coverage and parking. It also checks any overlay that applies. Examples:
     • a Community Standards District;
     • a hillside area;
     • a Significant Ecological Area;
     • oak trees;
     • the coastal zone;
     • a fire recovery area.
2. Building plan check by Public Works.
   • A plan check engineer at the district office reviews the structure, energy, plumbing, mechanical, electrical and green building sheets.
3. The Agency Referral sheet.
   • Early in plan check, the engineer marks the agencies your project needs. The header flags the conditions that drive most of them:
     • Very High Fire Hazard Severity Zone
     • sewer or septic
     • highway dedication
     • geology
     • methane
     • open code enforcement
     • whether a new address is needed
   • The sheet also warns that more clearances may be added later in plan check.
4. Each agency reviews on its own.
   • You submit plans, reports and forms directly to each one, on its own schedule.
   • You don’t have to wait for the agencies. The County lets building plan check start before the agency approvals are in, so the two run side by side. That saves time. The trade-off: when an agency comment moves a wall or adds sprinklers, the revised sheets go back through plan check, which can add time and plan check fees.
5. Fees and certificates.
   • School, library, sewer and other fees are paid to each agency, not to Building and Safety.
   • You bring back the proof: a certificate of payment, or a certificate of clearance if the project is exempt.
6. All approvals in, then the permit.
   • Every agency approval has to reach Building and Safety at least 48 hours before the permit can issue.
   • Deferred items. An agency may agree to let one item, such as the fire sprinkler plans, follow after the permit. The requirement doesn’t go away. It gets a later deadline, and it has to be met before the job is signed off.

Dates to watch:

• The review clock pauses. Under Government Code 65913.3, when another agency’s approval is required, the County’s time limits for reviewing your application stop running until you hand Building and Safety that approval. The referral sheet itself serves as the notice.
• Applications expire.
  • A County building application expires one year after you apply if no permit has issued (Title 26, Section 106.4.1.1).
  • The County can grant up to two extensions of up to 180 days each. You have to request them in writing, show that the delay was beyond your control, and pay a fee.
  • After that, you file a new application, resubmit the plans and pay plan check again.
• Fire approvals expire too. A Fire Department plan approval expires one year after Fire approves it if the building permit hasn’t issued by then. Up to two six-month extensions are allowed (Title 32, Section 106.2.4.2).
• Permits expire after issuance. An issued permit expires if work doesn’t start within 12 months, or if work stops for 180 days (Title 26, Section 106.5.4).

Not every project needs all of these. A typical ADU or addition needs four to eight. A rural or hillside site can need a dozen.

• Impact fees. Under Government Code 66311.5 (as in effect January 1, 2026), no impact fees on an ADU of 750 square feet or less, or a junior ADU of 500 square feet or less. Above that, fees must be proportional to the main house.
• School fees. An ADU or junior ADU under 500 square feet is treated as not adding 500 square feet of assessable space, so the school district fee generally does not apply. Larger units pay.
• Each fee is its own question. An exemption from impact fees doesn’t settle the school fee, the plan check fee or the utility charges. Check each one.
• Utility connections. A water or sewer agency cannot treat an ADU as a new residential use for connection fees unless it is built with a new single-family home. Where a separate connection is allowed, the charge has to be proportionate.
• Sprinklers. Not required in an ADU when the main house is not required to have them, unless they become Fire’s condition for a site with a short hydrant or long access.
• The 60-day clock covers zoning only.
  • State law gives the County 60 days to act on a complete ADU application. The Fire Department’s own guideline notes that this covers zoning review.
  • Building plan check, Fire review and the other agencies have no set timeline.
  • Their approvals also pause the County’s review clock until they are delivered.
• Addresses. An ADU needs its own address only when it has its own electric meter or its own driveway.

To protect our clients’ privacy, each project is identified by community and type only.

• Eaton Fire rebuild with a detached ADU, Altadena (2025).
  • Clearances:
    • Regional Planning
    • drainage
    • the debris recycling plan
    • Fire Prevention Engineering
    • the water company’s will-serve letter
    • Southern California Edison
    • the Sanitation Districts
    • Pasadena Unified school fees on the added floor area
  • Fire allowed the sprinkler plans to follow as a deferred item.
  • Permit cards for both buildings issued about seven weeks after building intake, and about five months after the Planning filing.
• Hillside ADU, Topanga (filed 2023).
  • Eleven clearances, including GMED, Waterworks District 29, Caltrans, Fuel Modification and the Los Angeles Unified school fee.
  • Fire first asked for 1,250 gallons per minute. The hydrant tested at 750.
  • The Waterworks District and Fire then confirmed that a lower flow requirement applied. The fuel modification plan was released in June 2024, and Fire cleared the project that July.
  • By then the building application had expired, and the County reopened it under a new number in October 2025.
  • The lesson: get the fire flow numbers before design, and watch the expiration date from day one.
• Garage conversion with a new attached garage, Acton (filed 2020).
  • The new driveway crossed an adjacent lot, so the County asked for an easement or a lot tie.
  • The septic review turned on how many bedrooms the system had to serve.
  • GMED asked for foundation sheets.
  • A Planning amendment was approved in January 2022, GMED cleared in February and Fire in April. The permit issued in May 2022, 20 months after the case opened.
• Two-story detached ADU, East San Gabriel (filed 2019).
  • Regional Planning could not sign off until the oak tree permit and the County Forestry fees were settled.
  • Fire took further correction rounds.
  • Also on the list: the fire flow form, drainage, the debris plan, school fees and a new address.
  • The permit issued about 19 months after plan check intake.
• Wildfire rebuild of a two-story home, Santa Monica Mountains (filed 2020).
  • The mailing address says Calabasas. The jurisdiction is the County.
  • Environmental Health was the last sign-off. The septic design had to match the bedroom count.
  • The project also worked through the fire flow form, a fuel modification covenant and several drainage rounds.
  • The fix was fewer bedrooms and revised plans backed by the old septic and debris records.
  • The permit issued 30 months after the case opened.
• Two-story addition, La Crescenta-Montrose (2017).
  • Regional Planning asked for proof that a 25-foot street dedication had been waived.
  • Public Works issued the approval letter about five months later. Review then moved on to drainage and building revisions.
• Addition, kitchen remodel and patio cover, Hacienda Heights (2022).
  • In August 2022, Fire asked for the water company’s fire flow form. It came back in December.
  • Building corrections followed in April 2023, and the permit issued that July.
  • A later change to remove a bearing wall needed its own supplemental permit.

How long County permits take in our files.

• Across 24 County home projects where we have both dates on record, the median was about 6.6 months from filing to permit. The middle half took roughly 4 to 10 months.
• The fastest took under 2 months from building intake: an Eaton Fire rebuild, which moves on the County’s recovery track.
• The slowest was the Santa Monica Mountains rebuild above, on septic, at about 30.
• Size didn’t predict it. The 209 square foot patio enclosure took 10 months from its referral sheet to permit.

Measured from the County case or plan check intake date to permit issuance.

• The referral sheet arrives after the design is done. By then a fire flow shortfall, a liquefaction zone or a septic limit can force a redesign. We read the parcel for these before design starts.
• Waiting on the water company. Will-serve letters and fire flow forms come from a separate company with its own timeline. In Hacienda Heights the fire flow form alone took four months, and the result can add sprinklers or a hydrant to the project.
• GMED on a lot that looks flat. A mapped liquefaction or landslide zone triggers a geology and soils review, regardless of how the lot looks from the street.
• Septic and bedrooms. Adding a bedroom can mean a bigger system, a new disposal field, or a smaller house.
• Agency comments that change the building plans. A Fire, GMED or Land Development comment often means a revised sheet, which goes back through Building and Safety.
• Sheets that grow mid-review. The County’s sheet says it plainly: additional clearances may be required by your plan check engineer.
• The one-year expiration. Long agency queues can push an application toward its expiration date. Extensions cost money, need a written reason, and stop at two. After that you start over with a new application and a new plan check fee.
• "It’s with the County." That status tells you very little. Ask which agency has it, whether the submittal is complete, and what the next action is.

Budget for four kinds of cost, not one:

1. Design and permit coordination.
2. Consultants, as the site needs them:
   • a structural engineer
   • energy compliance
   • a survey
   • a soils engineer
   • a civil engineer
   • a septic designer
   • an arborist
3. Agency fees: plan check, permit, and the fees on the referral sheet.
4. What the agencies require you to build:
   • a hydrant or sprinklers
   • drainage devices
   • a septic upgrade
   • retaining walls
   • a driveway approach

A fee to review a soils report doesn’t pay for writing it or revising it.

• Day one: we read the parcel. Before design, we check:
  • zoning, overlays and any Community Standards District;
  • fire hazard zone, seismic hazard and fault maps, flood zone and methane;
  • sewer or septic, the water company, the school district, and the County Library planning area;
  • frontage and highway dedication;
  • oak trees, trails, and any open code case.

  You get the likely clearance list before you commit to a design.

• Design for the clearances. Hydrant distance, access, fuel modification and drainage are drawn into the first set, not added after corrections.
• Submittal management through permit issuance. We file with Building and Safety and each agency, and we track every queue. We coordinate the licensed structural engineer and soils engineer, and we answer agency comments. We also keep the application ahead of its expiration date.
• Our County record.
  • As of October 2026: 8 Eaton Fire rebuilds designed, 7 in construction.
  • Projects in the Santa Monica Mountains, Topanga, Acton, the Antelope Valley, East San Gabriel, Hacienda Heights, La Crescenta-Montrose and other unincorporated communities.
  • Case study links (all County jurisdiction), each linked to its entry on /case-studies/:
    • the Altadena Eaton Fire rebuild;
    • the Altadena addition;
    • the Santa Monica Mountains fire rebuild;
    • the Acton project.

What to send us:

• the address and the Assessor’s Parcel Number (APN);
• a short description of what you want to build;
• any existing plans, permits or survey;
• any referral sheet, correction list or agency letter you already have;
• soils reports, septic records, water company letters and recorded easements, if you have them;
• anything you know about slopes, retaining walls, drainage problems, oak trees, a shared driveway, or work done without permits.

How do I know if my property is in unincorporated LA County?

Look up the address in the Public Works service locator at dpw.lacounty.gov/general/servicelocator. Your mailing city does not decide it. Many Pasadena, Calabasas, Inglewood and Whittier mailing addresses are in unincorporated County communities.

What is an Agency Referral sheet?

It is the form County Building and Safety issues during plan check. It lists every agency that must approve your project before the building permit can issue. Each agency is contacted, paid and cleared separately.

Who is responsible for getting the agency approvals?

The applicant. The County’s referral sheet says “Follow-up is your responsibility.” Every approval must be delivered to Building and Safety at least 48 hours before issuance. We handle this for our clients.

Does a Regional Planning approval mean I can build?

No. It settles zoning. Building plan check and every agency on the referral sheet still have to sign off before the permit issues.

Do small projects need agency clearances?

Often, yes. A 209 square foot patio enclosure of ours needed three: Regional Planning, Land Development and a debris recycling plan. The sheet also named the water company.

Does an ADU in the County pay school and library fees?

Under state law, an ADU under 500 square feet generally does not pay the school district fee, and an ADU of 750 square feet or less pays no impact fees. The Library still requires a certificate of clearance before the permit issues, even when no fee is owed.

My property already has water service. Why does Fire need a water form?

Your water service and fire flow are different questions. Fire needs to know what the nearest hydrant can deliver, and your water company reports it on Form 195 or 196. On one of our Topanga projects, Fire first asked for 1,250 gallons per minute and the hydrant tested at 750.

What if the water company says the hydrant can’t deliver enough flow?

The Fire Department may require fire sprinklers, a new or upgraded hydrant, or both. For an ADU outside a fire hazard zone, Fire’s guideline asks for 1,000 gallons per minute without sprinklers, or 500 with them.

What is GMED, and why does it want a report?

GMED is the County’s Geotechnical and Materials Engineering Division. It reviews geology and soils reports for sites in seismic hazard zones and on slopes. It also reviews reports for retaining walls, basements and deep foundations. Its approval is required before the permit issues.

How long does a County permit take?

There is no single honest number. Zoning review for an ADU has a 60-day state deadline. Building plan check, Fire and the other agencies have no set timeline, and the County’s review clock pauses while their approvals are outstanding. In our own files, the middle half of County home projects took roughly 4 to 10 months from filing to permit. Eaton Fire rebuilds moved faster. Septic, hillside and fire flow sites took longer. The application expires one year after you apply unless the County grants an extension, and it allows two at most.