Building permits, zoning and septic rules in unincorporated Imperial County, California

At a glance

Building permit

Required in unincorporated areas; unpermitted work is unlawful; issued by Planning & Development Services¹⁸

Zoning

Yes — reviewed as part of the building permit process under the county Land Use Code⁹

Septic permits

Imperial County Public Health, Environmental Health Division (OWTS/Land Use program)⁶

Owner-builder exemption

Available under state law, subject to who performs the work and limits tied to sale¹⁰

Well permits

Issued by the County Planning and Development Department¹¹

Permit processing time

At least 2 weeks minimum, longer with corrections or added agency review¹²

Tiny/manufactured homes

Occupancy can be approved when the unit, installation and location meet the applicable rules¹³¹⁴

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 Imperial County, California?

Yes. Unincorporated Imperial County makes it unlawful to erect, alter, move, repair or demolish a building or structure without first obtaining a building permit, and a separate permit is required for each building¹. Building permits are required to authorize new construction, alterations or additions to a building or structure, and virtually all construction, including minor modifications, requires a permit of some type¹². California also requires a separate permit for each building or structure before covered construction, alteration, repair, movement, improvement, removal, conversion or demolition begins¹⁵. The county's rules apply to unincorporated land; Brawley runs its own permits inside city limits, at least for swimming pools, spas and hot tubs¹⁶, and we could not confirm who issues general building permits inside El Centro or Calexico, so ask each city. Imperial County Planning & Development Services handles the local permit on unincorporated land, and California's Title 24 building standards apply through state adoption and local enforcement¹⁷. Processing takes at least 2 weeks, with more time possible for other agency approvals or plan-check corrections¹². The owner-builder exemption is from contractor licensing, not from permits or inspections¹⁸. It can cover an owner doing the work personally when the improvement is not intended for sale, or an owner contracting directly with properly licensed trade contractors, with additional conditions for homes built or improved for sale¹⁰.

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

Imperial County Planning & Development Services, at 801 Main St in El Centro, issues building, zoning, grading and mobile-home permits for the unincorporated county¹². A minimum submittal needs a signed permit application, a complete site plan, two copies of plans/details, a property owner acknowledgment form, and a contractor's workers'-compensation or owner-builder form, plus the applicable fee¹². Applicants can submit building permit and planning applications, track status, pay fees and request inspections through the Civic Access online platform; the county highly encourages it but still accepts physical applications¹⁹. Public Works, not Planning & Development Services, issues the separate encroachment or driveway permit you'll need if your access crosses county right-of-way, and Public Works also takes those applications through Civic Access¹²²⁰. The Public Works encroachment fee schedule we found dates from 2003 and lists a non-refundable $85 basic permit fee and an inspection fee of at least $85 per residential driveway, with work done without a permit charged at double; ask Public Works for the current schedule²¹. The Imperial County Air Pollution Control District charges a one-time operational development fee on new single-family homes, $285 at Level 1 or $654.50 at Level 2, paid when the building permit is issued; remodels of existing single-family homes and minor subdivisions of four or fewer dwellings are exempt²².

Does Imperial County have zoning?

Yes, for unincorporated land: zoning approval is required as part of the building permit process, and unincorporated Imperial County is zoned under the county's Land Use Code, Title 9, while incorporated cities administer their own: El Centro³, Calexico⁴ and Brawley⁵ each adopt zoning for land inside city limits, and the county's rules here apply to unincorporated land only⁹. California law allows counties to regulate building location, height, bulk, lot coverage, land-use intensity, parking and setbacks in unincorporated territory²³. The county's Title 9 land-use ordinance is the countywide zoning document, and a recent revision of its divisions was proposed at a countywide level²²⁴. We could not confirm numeric setbacks, minimum lot sizes, building-height limits or agricultural exemptions for the general zoning districts; ask Planning & Development Services for the rules tied to the parcel's zoning district before buying or designing. Parcel configuration matters too: Imperial County regulates owner-requested lot mergers under its Subdivision Ordinance, and the parcels must be contiguous and satisfy access and easement conditions²⁵. The department determines whether a lot-merger application is complete within 30 days after submittal, followed by a public hearing and required findings²⁵. For accessory dwelling units, an R-1 lot of 9,000 square feet or more and an R-2 lot of 6,000 square feet or more can qualify, R-2 development needs 4,500 square feet of lot area per family dwelling unit, and an ADU built above a garage needs a side and rear setback of no more than 4 feet²⁶²⁷.

How do septic permits work in Imperial County?

Septic systems in Imperial County go through the Public Health Department's Environmental Health Division, not the building department directly⁶. The Land Use program protects the environment and public health through a review process of proposed land use in Imperial County — it consists of the review of on site wastewater treatment system (septic system) design plans and inspects the construction of on site wastewater treatment system (OWTS)s to prevent threats to public health²⁸. That review isn't optional for a building permit: we also review applications for building permits on lots served by OWTSs, and Planning & Development Services' own checklist requires a percolation test for the septic tank, leach field and reserve leach field if the lot isn't on public sewer²⁸¹². Soils are a moderate constraint countywide: USDA data rates only 11% of Imperial County's soils as free of severe limits for a conventional septic drain field, so budget for a site evaluation before you assume a standard system will work²⁹. Statewide, California's OWTS Policy is implemented by local agencies like Imperial County's Environmental Health Division under a Regional Water Board-approved Local Agency Management Program³⁰. Where public sewer is unavailable, unincorporated Imperial County premises must obtain an onsite permit from the county, and no septic permit is issued for a lot that can connect to public sewer³¹. For a failing system, connecting to a public sewer is an option when one is available within 200 feet of the property³². The county fee schedule lists $856 for a new, alteration or full-replacement sewage-system permit, which includes one inspection; additional inspections are charged at an hourly rate⁷³³. Inside an incorporated city, the county administers septic rules only with the city's written authorization, so ask the city and Environmental Health which applies³⁴. Where the county's program does not apply, new and replacement systems must meet the state's Tier 1 low-risk standards³⁵.

Can you live in an RV or tiny home on your land in Imperial County?

Imperial County's local rule for living in an RV on private land remains unconfirmed, so ask Planning & Development Services about the parcel and proposed use before moving one onto the site. California does not treat an RV as a permanent dwelling, and RV occupancy generally is limited to mobilehome parks or special occupancy parks unless a local ordinance allows another arrangement³⁶. A tiny home can be occupied only when it meets the standards for, and is approved as, a recognized type such as a manufactured home, code-built home, factory-built home, RV, park trailer or camping cabin; the location must also be approved for that classification¹³. A manufactured home may be occupied inside or outside a mobilehome park after the required installation and occupancy approval, while local land-use, building, health, safety and site requirements still apply¹⁴. A tiny home that meets the state definition of an accessory dwelling unit is subject to state ADU law; one that does not is not established as permitted³⁷. A manufactured home can also serve as an accessory dwelling unit under state ADU law, which does not by itself allow placement outside that context³⁸. State rules that let one RV, or one tent or camping cabin, sit on a lot apply only inside a licensed special occupancy park, so they do not answer whether you can live in an RV on your own parcel³⁹⁴⁰. Planning & Development Services oversees mobilehome-park construction, use, maintenance and occupancy locally¹².

What are the steps to build a home in Imperial County, in order?

1. Confirm the parcel's zoning district and ask Planning & Development Services for its setbacks, lot coverage and allowed residential uses⁹.
2. Confirm that the legal parcel configuration supports the project; lot mergers in unincorporated Imperial County follow the county Subdivision Ordinance²⁵.
3. If there is no public sewer, start the septic design, percolation testing and Environmental Health review before the building application²⁸¹².
4. Decide whether to hire licensed contractors or qualify as an owner-builder; owner-builder status does not waive permits or inspections¹⁸.
5. Submit the building plans to Planning & Development Services and allow at least 2 weeks for processing, plus time for corrections or other agency approvals¹².
6. Obtain a well permit through the County Planning and Development Department if the project includes a new or reconstructed well¹¹.
7. Ask Public Works about an encroachment or driveway permit if access crosses county right-of-way¹².

What should you check before you buy land in Imperial County?

Confirm your parcel's zoning district and access to public sewer or water with Planning & Development Services, since both drive your permit path and septic requirements⁹. Budget for a real septic site evaluation: only 11% of county soils are rated free of severe limits for a conventional drain field²⁹. This is a hot, dry desert county — average annual precipitation is just 3.2 inches, and the county is projected to see 128.4 days a year at or above 100°F by mid-century, so cooling costs and water planning matter more here than almost anywhere else in this guide's coverage⁴¹⁴². A large share of the county, 69%, is federal land, which shrinks the buildable private-land footprint and can affect access and utility easements nearby⁴³. Typical farmland runs about $11,892 an acre and the median home value is $380,919, while the median property tax bill is $2,348 a year at an effective rate of 0.8%^44454647.

Watch-outs

• Imperial County Planning & Development Services now takes building permit and planning applications through its Civic Access online platform, though physical applications are still accepted; confirm current submittal steps before you apply¹⁹.
• We could not confirm Imperial County's numeric setback, minimum lot size, building height or agricultural-exemption rules, or its local rule for RV occupancy; ask Planning & Development Services before you design, buy or move an RV onto the land⁹.

Sources

1. Title 9, Division 9, Chapter 2, § 91002.06 — Permit required, quoted and re-checked
2. “Lot Mergers”: What They Are, Why They Happen, and How the Process Works, quoted and re-checked
3. El Centro: Building & Zoning Codes (Imperial County), quoted and re-checked
4. Calexico: Planning Division (Imperial County), quoted and re-checked
5. Brawley: Sec. 27.70. - Residential districts (Imperial County), quoted and re-checked
6. Imperial County Local Agency Management Program (2026 county census)
7. Imperial County Local Agency Management Program, quoted and re-checked
8. Title 9, Division 9, Chapter 2, § 91002.06 — Permit required (2026 county census)
9. “Lot Mergers”: What They Are, Why They Happen, and How the Process Works (2026 county census)
10. California Business and Professions Code § 7044, quoted and re-checked
11. Water Programs, quoted and re-checked
12. Imperial County Planning & Development Services (icpds.com)
13. Information Bulletin 2016-01 Tiny Homes, quoted and re-checked
14. Information Bulletin 2016-01 Tiny Homes, quoted and re-checked
15. Do I need a building permit for my project? (California statewide rule), quoted and re-checked
16. Brawley: Sec. 23B.10. - Uniform Swimming Pool Code—Adopted; where filed (Imperial County), quoted and re-checked
17. California Health and Safety Code section 17922, quoted and re-checked
18. California Code, BPC 7044, quoted and re-checked
19. Imperial County Planning & Development Services Launches New Online Permitting Portal, quoted and re-checked
20. Apply for Public Works Permits, quoted and re-checked
21. Master Fee Schedule Inventory, quoted and re-checked
22. Rule 310 - Operational Development Fee, quoted and re-checked
23. California Government Code Section 65850 (California statewide rule), quoted and re-checked
24. icpds.com, quoted and re-checked
25. “Lot Mergers”: What They Are, Why They Happen, and How the Process Works, quoted and re-checked
26. Title 9, Division 4, Chapter 1, § 90501.13 — Accessory dwelling unit, quoted and re-checked
27. Title 9, Division 4, Chapter 5, § 90405.03 — Accessory dwelling units, quoted and re-checked
28. Imperial County Public Health Department, Environmental Health Division (icphd.org)
29. 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
30. Water Quality Control Policy for Siting, Design, Operation and Maintenance of Onsite Wastewater Treatment Systems (OWTS Policy) (California statewide rule), quoted and re-checked
31. Information Sheet Resolution R7-2016-0020 Approving the Local Agency Management Program for Imperial County, quoted and re-checked
32. Imperial County Local Agency Management Program, quoted and re-checked
33. Imperial County Local Agency Management Program, quoted and re-checked
34. Imperial County Local Agency Management Program, quoted and re-checked
35. Imperial County Local Agency Management Program, quoted and re-checked
36. hcd.ca.gov (California statewide rule), quoted and re-checked
37. Accessory Dwelling Unit Handbook, March 2026, quoted and re-checked
38. Accessory Dwelling Unit Handbook, March 2026, quoted and re-checked
39. hcd.ca.gov, quoted and re-checked
40. hcd.ca.gov, quoted and re-checked
41. Annual precipitation: Bolthole Index county data
42. Projected mid-century days at or above 100°F: Bolthole Index county data
43. Federal land share: Bolthole Index county data
44. Farmland value per acre (USDA census): Bolthole Index county data
45. Typical home value (Zillow): Bolthole Index county data
46. Median property tax bill: Bolthole Index county data
47. Effective property tax rate: Bolthole Index county data

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.