Unincorporated Ventura County, California generally requires a building permit from the county's Resource Management Agency before construction, although some small projects and minor improvements are exempt1. Every unincorporated parcel has county zoning, under separate Coastal and Non-Coastal ordinances, while incorporated cities run their own zoning23. RMA Environmental Health issues septic permits only in unincorporated areas, where each new system needs a site-specific evaluation45.
At a glance
- Building permit
- Generally required before construction in unincorporated Ventura County, with exemptions for some small projects and minor improvements1
- Zoning
- Every unincorporated parcel is zoned under either the Coastal or Non-Coastal ordinance; cities administer their own zoning23
- Septic
- RMA Environmental Health handles unincorporated areas; each new system requires a site-specific evaluation45
- Owner-builder
- California's owner-builder exemption covers contractor licensing only; the county still requires a permit in the owner's name, a Notice to Property Owner acknowledgment and an inspection67
- RV living
- Temporary RV housing is allowed during permitted home construction; non-coastal RV parks limit stays to 90 days in any 120-day period891011
- Tiny homes
- A tiny home outside the manufactured-home, factory-built, RV, park-trailer and camping-cabin classes must meet the California Building Standards Code; RV-style tiny homes in non-coastal RV parks are limited to 90 days in any 120-day period1213
- Minimum home size
- No county minimum confirmed; California's efficiency-unit standard sets 190 square feet of living space, or 150 square feet where a local ordinance allows it14
- Wells
- The countywide moratorium on new well permits in unincorporated areas has been lifted, but local moratoria in some basins may still apply15
- Federal land
- About 52% of the county is federal land (Los Padres National Forest and the Channel Islands)16
Who to call
Building permits
Ventura County Resource Management Agency, Building and Safety Division
Building permits and code enforcement for unincorporated Ventura County
800 S Victoria Ave, Ventura, CA 93009
Zoning
Ventura County Resource Management Agency, Planning Division
Zoning ordinance administration, permit applications and 'What's My Zoning' lookups for unincorporated Ventura County
800 S Victoria Ave, Ventura, CA 93009
Septic permits
Ventura County Resource Management Agency, Environmental Health Division
Onsite wastewater treatment system (OWTS/septic) design review, construction and repair permits, and inspections for unincorporated Ventura County; has no jurisdiction inside city limits or over systems serving mobile home parks
800 S Victoria Ave, Ventura, CA 93009
Contact details are copied from each office’s official page and were checked against it on October 16, 2026.
Off-grid gear
Going off-grid in Ventura County means bringing your own water and power. The kit we’d start with:
- Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
- Power Bluetti Solar generators and home battery backup for living off the grid.
- Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
- Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.
These are affiliate links — we may earn a commission, at no cost to you. As an Amazon Associate, Bolthole Index earns from qualifying purchases.
Do you need a building permit in Ventura County, California?
Yes. Buildings and structures in unincorporated Ventura County generally need a permit from RMA Building and Safety before construction starts, but some small storage sheds, flooring and most residential finish work are exempt; public schools, hospitals, utility infrastructure and public-right-of-way projects also fall outside the ordinary county permit rule1. Work that needs a permit is inspected by the Building Division: the owner or contractor calls for each inspection, and required work must stay exposed until the Building Official approves it17. California's owner-builder exemption concerns contractor licensing, not the permit or inspection requirements6. In Ventura County, the owner-builder permit is taken out in the owner's name, and Building and Safety requires a signed Notice to Property Owner acknowledging liability, plus verified owner identification, before issuing it7.
Who is the Ventura County building department, and how do you reach them?
RMA Building and Safety issues building permits for unincorporated Ventura County only1. Inside Camarillo and Fillmore, the city's own office handles building permits1819; in every other incorporated city, call that city's building department. RMA Building and Safety is at 800 S Victoria Ave, Ventura, CA 93009, phone (805) 654-2494, and permits can also be tracked through the county's OneStopPermits portal20. Construction in unincorporated Ventura County is governed by the 2025 Ventura County Building Code, which adopts the current California Building Standards Code with county-specific amendments21. Fees aren't a flat number: Building and Safety calculates them based on the size, scope and value of your specific project during the permitting process22.
Does Ventura County have zoning, and does it matter which zone you're in?
Yes. Every parcel in unincorporated Ventura County has a county zoning designation2. RMA Planning applies the Coastal Zoning Ordinance in the Coastal Zone and the Non-Coastal Zoning Ordinance elsewhere; the two codes differ in substantive ways323. Inside Camarillo, Fillmore, Simi Valley and Port Hueneme, the city's own code sets zoning instead24252627. In the Non-Coastal ordinance, lot coverage, setbacks and height are set district by district, so no single countywide number applies2829. Setbacks are an example: RA zoning requires 5 feet on the interior side and 10 feet at the rear, while OS-REC requires 20 feet at the front29. Height in OS-REC starts at 25 feet and can rise to 35 feet when each side-yard setback is at least 15 feet30. Greenhouses and similar plant-growing structures on agriculturally designated lots are excluded from the lot-coverage maximum28. In the non-coastal area, an accessory dwelling unit can be approved directly with a building permit, and a manufactured home can serve as the ADU3132. For minimum home size, Ventura County's reviewed materials show no separate local rule; California's efficiency-unit standard calls for at least 190 square feet of living space, or 150 square feet if a local ordinance allows it14.
How do septic (OWTS) permits work in Ventura County?
RMA Environmental Health is the OWTS authority for unincorporated Ventura County; the city building department is the contact for systems inside city limits, while mobile home park systems are outside the county division's jurisdiction433. Septic permits stay with Environmental Health or the city, never with RMA Building and Safety, even where a city issues its own building permits. Off-grid sanitation is possible through an OWTS where public sewer is unavailable, but every new system needs an individual site evaluation before a Permit to Construct is issued5. Septic permits and inspections cover both new systems and repairs3435. A property requiring a conventional OWTS must connect when an available public sewer line is within 200 feet36. For an alternative OWTS, the public-sewer connection threshold is one-half mile37. Only about 11.1% of county soils avoid severe limits for a conventional drain field, so establish feasibility early38.
Can you live in an RV or tiny home on your land in Ventura County?
Ventura County's confirmed RV-on-private-land allowances are tied to construction, not a general right to live in an RV. In the unincorporated non-coastal area, a Zoning Clearance may authorize one habitable RV for up to 12 months during permitted construction or major remodeling of a principal dwelling, with up to two additional 12-month periods for substantial progress8. The Coastal Zone allows an owner's RV for 12 months during permitted home construction, with one additional 12-month period for substantial progress and required permanent water and sewage connections9. In non-coastal RV parks, each RV or its occupants may stay no more than 90 days in any 120-day period; those parks require a Conditional Use Permit and are limited to specified zones1011. A tiny home outside the manufactured-home, factory-built, RV, park-trailer or camping-cabin classifications is a dwelling and must comply with the California Building Standards Code for legal occupancy12. Tiny-home-style RVs, travel trailers and truck campers in non-coastal RV parks share that limit; such parks need at least 3 acres on one legal lot, allow no permanent structure attached to a space, and are allowed only in OS-REC, OS, RA and RE zones with a Conditional Use Permit3913. Manufactured homes may be dwellings in an authorized unincorporated mobilehome park, subject to the overlay, base-zone, building and state requirements40. Ventura County has not confirmed a general rule for overnight camping outside parks or construction allowances; ask RMA Planning about the parcel and unit23.
Building a home in Ventura County: the steps, in order
- Confirm the parcel's Coastal or Non-Coastal zoning with RMA Planning, and determine whether any proposed lot split or lot-line adjustment must follow the county Subdivision Ordinance2341.
- If you need a well, ask about restrictions in the parcel's groundwater basin; local moratoria may remain even though the countywide unincorporated-area moratorium was lifted15.
- If public sewer is unavailable, obtain a site-specific OWTS evaluation from RMA Environmental Health before fixing the site plan533.
- Apply through RMA Building and Safety under the 2025 Ventura County Building Code, and sign the Owner-Builder Declaration if applicable20217. Call for each inspection and keep required work exposed until it passes17.
- If the site lies in a FEMA-designated 1% annual-chance floodplain, obtain a Floodplain Development Permit before construction42.
What to check before you buy land in Ventura County
Confirm the parcel's Coastal or Non-Coastal zoning and whether a proposed division, merger or lot-line adjustment triggers the Ventura County Subdivision Ordinance4341. In the Non-Coastal Zoning Ordinance, minimum lot area runs by district: RA is 1 acre, OS is 10 acres and AE is 40 acres, so confirm the district before assuming a parcel can be split44. For wastewater, only about 11.1% of county soils avoid severe limits for a conventional drain field, and each new OWTS needs site-specific evaluation385. Check the groundwater basin because local well moratoria may remain15. A FEMA 1% annual-chance floodplain designation requires a development permit for habitable and non-habitable structures42. About 52% of the county is federal land, which limits the private rural inventory16. The effective property-tax rate is about 0.7%, and the median annual bill is about $5,3264546.
Watch-outs
- Ventura County's Coastal and Non-Coastal RV-during-construction allowances have different approval, extension and utility conditions; use the rule for the parcel's zoning area89.
- Short-term rentals are not permitted in the Non-Coastal Ojai Temporary Rental Unit Regulation Overlay Zone unless the dwelling was classified as a historic landmark as of June 19, 2018; homeshares may operate separately with a county permit47.
- We could not confirm how Ventura County classifies a tiny home as a primary or accessory dwelling on a particular parcel, or rules for a county driveway-access standard or certificate of occupancy; confirm the proposed classification and site with RMA2023.
- Well-permit moratoria in Ventura County are basin-specific and can change; even though the countywide moratorium in unincorporated areas has lifted, a city or Groundwater Sustainability Agency may still have its own restriction in effect for your specific basin15.
- An agricultural shed under the 2025 Ventura County Building Code is exempt from a building permit only up to 120 square feet and more than 60 feet from other non-residential buildings larger than 6,000 square feet on the same parcel, and the exemption does not remove zoning, fire, health or environmental requirements48.
- The agricultural exemption in the county's Habitat Connectivity and Wildlife Corridor rules covers activities such as commercial crops, internal driveways and certain fencing, but it is not a blanket exemption from building, zoning, fire or septic permits49.
Sources
- Building Permit Information - Ventura County Resource Management Agency, quoted and re-checked
- County Ordinances - Ventura County Resource Management Agency, quoted and re-checked
- County Ordinances - Ventura County Resource Management Agency, quoted and re-checked
- Septic Systems / Wastewater Disposal, quoted and re-checked
- Septic Systems / Wastewater Disposal, quoted and re-checked
- Before Applying for a License When No Exam is Required, quoted and re-checked
- Considering Becoming an Owner-Builder? - Ventura County Resource Management Agency, quoted and re-checked
- Ventura County Non-Coastal Zoning Ordinance (9-16-2025 edition), quoted and re-checked
- Ventura County Coastal Zoning Ordinance, quoted and re-checked
- Ventura County Non-Coastal Zoning Ordinance (9-16-2025 edition), quoted and re-checked
- Ventura County Non-Coastal Zoning Ordinance (9-16-2025 edition), quoted and re-checked
- HCD Information Bulletin 2016-01: Tiny Homes, quoted and re-checked
- Ventura County Non-Coastal Zoning Ordinance, quoted and re-checked
- California Health and Safety Code § 17958.1, quoted and re-checked
- Water Well Permit Restrictions, quoted and re-checked
- Federal land share: Bolthole Index county data
- Inspections - Ventura County Resource Management Agency, quoted and re-checked
- Camarillo: City of Camarillo Master Fee Schedule (Ventura County), quoted and re-checked
- Fillmore: Building & Safety | Fillmore, CA (Ventura County), quoted and re-checked
- Ventura County Resource Management Agency, Building and Safety Division (rma.venturacounty.gov)
- Ventura County Building Code (Current Edition), quoted and re-checked
- Permit Fees Collected by Building and Safety, quoted and re-checked
- Ventura County Resource Management Agency, Planning Division (rma.venturacounty.gov)
- Camarillo: Camarillo Code § 19.14.050 — R-1 lot area and lot width (Ventura County), quoted and re-checked
- Fillmore: 6.04.0415 - Zoning district development standards (Ventura County), quoted and re-checked
- Simi Valley: Simi Valley Municipal Code 9-24.020 Purposes of Residential and Open Space Zoning Districts (Ventura County), quoted and re-checked
- Port Hueneme: Port Hueneme Code 10403 R-1 Development standards (Ventura County), quoted and re-checked
- Ventura County Non-Coastal Zoning Ordinance, quoted and re-checked
- Ventura County Non-Coastal Zoning Ordinance, quoted and re-checked
- Ventura County Non-Coastal Zoning Ordinance, quoted and re-checked
- Accessory Dwelling Units - Ventura County Resource Management Agency, quoted and re-checked
- Accessory Dwelling Units - Ventura County Resource Management Agency, quoted and re-checked
- Ventura County Resource Management Agency, Environmental Health Division (rma.venturacounty.gov)
- Onsite Wastewater Treatment System (OWTS) Construction and Repair, quoted and re-checked
- Septic Systems / Wastewater Disposal, quoted and re-checked
- rma.venturacounty.gov, quoted and re-checked
- New Onsite Wastewater Treatment Systems Design, quoted and re-checked
- 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
- Ventura County Non-Coastal Zoning Ordinance, quoted and re-checked
- Mobilehome Park Overlay Zone and Regulations, quoted and re-checked
- onestoppermits.venturacounty.gov, quoted and re-checked
- Engineering Services Department, quoted and re-checked
- County Ordinances - Ventura County Resource Management Agency (2026 county census)
- Ventura County Non-Coastal Zoning Ordinance, quoted and re-checked
- Effective property tax rate: Bolthole Index county data
- Median property tax bill: Bolthole Index county data
- Temporary Rental Unit Ordinance Frequently Asked Questions, quoted and re-checked
- Ventura County Building Code (Current Edition), quoted and re-checked
- Habitat Connectivity and Wildlife Corridor FAQ, 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.