Building permits, zoning and septic rules in unincorporated Los Angeles County

At a glance

Building permit

Required in unincorporated areas; which office handles it depends on your address (use the online Service Locator)⁷

Zoning

Yes; Title 22 zones every parcel outside the county's 88 cities²³

Septic

County-permitted through Public Health's Local Agency Management Program, not Public Works⁵

RV occupancy

Generally not allowed on private property; a shelter-crisis exception has strict lot, occupancy and siting conditions⁸⁹

Manufactured home living

Allowed on a vacant parcel with county approval, as a certified double-wide on a permanent foundation¹⁰

Accessory dwelling (ADU)

Allowed with county review; a junior ADU is capped at 500 square feet¹¹

Minimum home size

800 square feet in the listed single-family zones, modifiable with a Minor Conditional Use Permit¹²

R-1 lot size / setbacks / height

Generally 5,000 square feet per lot; 20-foot front, 15-foot rear and 5-foot side yards; 35-foot height; exceptions apply¹³¹⁴¹⁵

Who to call

Contact details are copied from each office’s official page and were checked against it on October 16, 2026.

Do you need a building permit in unincorporated Los Angeles County?

Unincorporated Los Angeles County requires a permit before you build, add on, alter, move or demolish a structure, or work on its electrical, mechanical or plumbing systems¹⁷. Like the counties around it in California, Los Angeles County requires a county building permit¹. The 2025 California Building Standards Code applies to buildings and structures with a permit application date on or after January 1, 2026¹⁶. The county adds amendments to the state code for Southern California construction concerns¹⁷. Once a permit issues, request the first inspection within 12 months and schedule follow-up inspections every 6 months to keep it active¹⁸. California's owner-builder exemption can remove the contractor-license requirement in qualifying cases, but it does not remove building permits or inspections¹⁹.

Who is the Los Angeles County building department, and how do you reach them?

Los Angeles County Public Works, Building and Safety Division, issues building permits for unincorporated communities through 10 district offices rather than one central counter⁴. Start with the county's online Service Locator and your street address or parcel number; it tells you which office handles your permit²⁰. The division's headquarters is at 900 S. Fremont Avenue, 3rd Floor, in Alhambra, with the Building Plan Check line at (626) 458-3173⁴. Applications, plan uploads, fee payment and status tracking run through the county's EPIC-LA system²⁰. The county's rules apply to unincorporated land. Inside Azusa, the city's own office handles building permits²¹; for other cities, confirm with the city before applying to the county. Septic permits stay with Public Health in every case⁵.

Does Los Angeles County have zoning?

Unincorporated Los Angeles County is fully zoned: Title 22 applies to every property, use, building and structure outside the county's cities, and every parcel has a specific zone on file with LA County Planning²²²²³. Cities set their own zoning, including Long Beach²⁴, Pasadena²⁵, West Covina²⁶ and Azusa²⁷; Title 22 does not apply there³. In the R-1 zone, the general minimum lot is 5,000 square feet, with a 20-foot front yard, 15-foot rear yard, 5-foot side yard and a 35-foot height limit; special districts can change those figures¹³¹⁴¹⁵. The A-1 Light Agriculture zone also starts at 5,000 square feet, but animals, structures and uses add 1 to 5 acres²⁸. Single-family homes in R-1, A-1 and several other listed zones generally need at least 800 square feet of floor area¹². Confirm the parcel's zone and any Community Standards District with LA County Planning before buying²⁹³⁰.

How do septic permits work in Los Angeles County?

Septic systems in unincorporated Los Angeles County are reviewed and approved by the Department of Public Health's Environmental Health division under its Local Agency Management Program, not by Public Works³¹³². Plan approval must come before any construction, installation, alteration or repair of an onsite wastewater system³³. For a new home or bedroom addition without public sewer within 200 feet, the dispersal area and a future replacement area must be designated and tested, with a feasibility report, plot plan and floor plan³⁴. The county will not approve a new septic system when a public sewer is available within 200 feet of the building³⁵. Public Health does site and installation inspections before final design approval, and that approval then goes to Building and Safety for the building permit³⁶. Incomplete submittals are not accepted, and plan status is promised within 20 business days³⁴. Soils are a real constraint: only about 7% of county soils lack severe limitations for a conventional drain field, so non-conventional systems may be needed³⁷³⁸. Chemical toilets are limited to non-residential, short-term uses and are not a substitute for a septic system³⁹.

Can you live in an RV, manufactured home or tiny home on your land in Los Angeles County?

Living in an RV or trailer on private property in unincorporated Los Angeles County is generally not allowed for any length of time; the exceptions are disaster housing, a permitted RV park and the Interim and Supportive Housing Ordinance⁶. During a county-declared shelter crisis, one occupied RV may sit behind an owner-occupied single-family home on a lot of at least 5,000 square feet, rent-free, if it is operative, meets setbacks, stays at least 6 feet from buildings and ends occupancy within 30 days after the crisis expires⁹. Occupied RVs are not allowed on vacant lots⁹. Title 22 campgrounds are tent-camping uses that exclude permanent occupancy, and in the agricultural zones they need review such as a CUP in A-1⁴⁰. A certified double-wide manufactured home may serve as a single-family residence on a vacant parcel with county approval and an approved permanent foundation; a single-wide may qualify only as an ADU or temporary quarters during construction¹⁰. California treats a tiny home on a chassis with axles and 400 square feet or less of floor area as an RV, so the RV rule applies; a tiny home on a foundation must meet the building code⁴¹⁴². Ask LA County Planning to classify the unit before you buy³⁰. Accessory dwellings are allowed with county review, and a junior ADU is capped at 500 square feet¹¹.

How do you build a home in unincorporated Los Angeles County?

1. Use the county's Service Locator with your address or parcel number to find which Building and Safety office serves the property²⁰.
2. Confirm the parcel's zone, setbacks, height and any Community Standards District rules with LA County Planning before finalizing the site plan³⁰²⁹. Dividing land is a discretionary process: a tentative map goes to the County Subdivision Committee and a public hearing⁴³.
3. Apply through EPIC-LA and upload plans and required attachments²⁰.
4. Budget separately for Planning filing fees, development-impact fees and Building and Safety permit fees; the published Planning schedule is not a complete construction-permit fee table⁴⁴.
5. Get septic plan approval from Public Health before any onsite-wastewater installation begins³²³³.
6. Once the building permit issues, request the first inspection within 12 months and keep follow-up inspections on a 6-month cadence until closeout¹⁸.

What should you check before buying rural land in Los Angeles County?

Only about 31% of Los Angeles County land has a slope of 15% or less, so verify grading, road access and a feasible building pad for the parcel⁴⁵. Any driveway or access road meeting a public right-of-way must maintain sight distance acceptable to Public Works, and walls, fences, structures or storage near the property-line entrance may be reviewed⁴⁶. Public Works may also use its access guidelines when setting conditions for developments subject to discretionary approval or specified improvement requirements⁴⁷. Severe drought has occurred in roughly 41% of years, so investigate a lawful water source⁴⁸. California requires a local permit before a water well is constructed, modified or destroyed⁴⁹. In Los Angeles County, the Department of Public Health's Drinking Water Program reviews and approves wells, except in Long Beach, Pasadena and Vernon, which have their own environmental health departments⁵⁰. Dewatering or stabilizing wells for excavations and hillsides do not need a well permit⁵¹. Flood Protection Districts regulate land Public Works identifies as subject to substantial flood hazard⁵². After the Eaton Fire, a rebuild with added bedrooms on an existing cesspool must upgrade to septic or connect to sewer within 200 linear feet, subject to funding⁵³. Short-term rentals are allowed only as an accessory use to a registered primary residence⁵⁴.

Watch-outs

• The occupied-RV shelter-crisis exception is not permission to camp on a vacant parcel; it requires an owner-occupied home and the other siting, sanitation and time conditions⁹.
• The detailed driveway width and slope standard applies to parking areas serving three or more dwelling units; a single-home entrance still must provide sight distance acceptable to Public Works⁵⁵⁴⁶.
• We could not confirm a general agricultural exemption from county zoning, building or land-use rules; ask LA County Planning before assuming a farm or ranch building is exempt³⁰.
• Setback and lot-size figures come from a county summary that points readers to Planning's current site for updates, so confirm them for your parcel¹⁴.

Sources

1. Building and Safety - LA County Public Works Permits (2026 county census)
2. Los Angeles County Code Title 22: Planning and Zoning (2026 county census)
3. Los Angeles County Code Title 22: Planning and Zoning, quoted and re-checked
4. Los Angeles County Public Works, Building and Safety Division (pw.lacounty.gov)
5. Local Agency Management Program (LAMP), quoted and re-checked
6. Common Zoning Violations - LA County Planning, quoted and re-checked
7. Building and Safety - LA County Public Works Permits, quoted and re-checked
8. planning.lacounty.gov, quoted and re-checked
9. file.lacounty.gov, quoted and re-checked
10. FAQs - LA County Planning, quoted and re-checked
11. Accessory Dwelling Units - LA County Planning, quoted and re-checked
12. Los Angeles County Title 22 – Planning and Zoning, Volume 1, quoted and re-checked
13. Zone R-1: Single Family Residence, quoted and re-checked
14. Zone R-1: Single Family Residence, quoted and re-checked
15. Zone R-1: Single Family Residence, quoted and re-checked
16. Approved Building Standards (California statewide rule), quoted and re-checked
17. Los Angeles County Public Works Fiscal Year 2024-2025 Report, quoted and re-checked
18. Building and Safety - LA County Public Works Permits, quoted and re-checked
19. Building Officials - Owner-Builder Overview, quoted and re-checked
20. Permits Overview - LA County Public Works Permits, quoted and re-checked
21. Azusa: Building Permits (Los Angeles County), quoted and re-checked
22. Los Angeles County Code Title 22: Planning and Zoning, quoted and re-checked
23. Land Use and Zoning - LA County Planning, quoted and re-checked
24. Long Beach: LBMC 21.31.205 Units per lot and lot area per unit (Los Angeles County), quoted and re-checked
25. Pasadena: Pasadena Zoning Code 17.80.020 Definitions (Los Angeles County), quoted and re-checked
26. West Covina: West Covina Code Sec. 26-89 General provisions (parking) (Los Angeles County), quoted and re-checked
27. Azusa: Development Code (Los Angeles County), quoted and re-checked
28. Title 22 - Agricultural Zones (effective 2019-02-28), quoted and re-checked
29. Land Use and Zoning - LA County Planning, quoted and re-checked
30. Los Angeles County Department of Regional Planning (LA County Planning) (planning.lacounty.gov)
31. Onsite Wastewater Treatment System, quoted and re-checked
32. LA County Department of Public Health, Environmental Health – Onsite Wastewater Treatment Program (admin.publichealth.lacounty.gov)
33. admin.publichealth.lacounty.gov, quoted and re-checked
34. Requirements and Procedures for Conventional and Non-Conventional Onsite Wastewater Treatment Systems, quoted and re-checked
35. New Ordinance Adopted - Local Agency Management Program, quoted and re-checked
36. Onsite Wastewater Treatment System, quoted and re-checked
37. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
38. Onsite Wastewater Treatment System | Los Angeles County Department of Public Health, quoted and re-checked
39. New Ordinance Adopted - Local Agency Management Program, quoted and re-checked
40. Los Angeles County Code Title 22, Planning and Zoning, quoted and re-checked
41. Information Bulletin 2016-01 (MH, FBH, SHL, MP/SOP, RT, OL) — Revised: Tiny Homes, quoted and re-checked
42. Common Zoning Violations - LA County Planning, quoted and re-checked
43. Planning Permits, quoted and re-checked
44. Fees - LA County Planning, quoted and re-checked
45. Share of land at 15% slope or less: Bolthole Index county data
46. planning.lacounty.gov, quoted and re-checked
47. Access Management for Private Developments Guidelines Manual, quoted and re-checked
48. Share of years in severe drought: Bolthole Index county data
49. Well Standards (California statewide rule), quoted and re-checked
50. State Small Water Systems and Wells, quoted and re-checked
51. State Small Water Systems and Wells, quoted and re-checked
52. Los Angeles County Code Title 22, Flood Protection Districts, quoted and re-checked
53. Onsite Wastewater Treatment System | Los Angeles County Department of Public Health, quoted and re-checked
54. Short-Term Rental Ordinance/Title 22 Project Summary, quoted and re-checked
55. Los Angeles County Code Title 22, Planning and Zoning, quoted and re-checked

Written October 16, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.