Bolthole Index

Colusa County, California

Building permits, zoning and land rules in Colusa County, California

44Index Score / 100
#26 of 58 in California

Unincorporated Colusa County, California requires building permits for new buildings and many alterations, and all applications go through the county's online permit portal12. County zoning controls allowed uses, setbacks and building dimensions parcel by parcel3. Septic systems and wells are permitted separately by the Colusa County Environmental Health Division45.

At a glance

Building permit
Required for new buildings and many additions, renovations and building-system projects1
Zoning
Yes; allowed uses and development standards vary by parcel and zoning district36
Septic
Environmental Health requires a permit to construct, reconstruct or repair an onsite system78
RV living
No permanent RV residence; temporary occupancy during home construction requires a Temporary Use Permit9
Tiny home
A qualifying park-trailer tiny home may serve as an accessory dwelling unit after foundation, utility and design conditions are met10
Owner-builder
Available conditionally; the county permit form requires an owner-builder declaration11
Water well
A county permit is required for a new well, modifications or abandonment5

Who to call

Building permits

Colusa County Building Department

Building permit applications, plan and code-compliance review; the coordinated review also sends plot plans to Planning for zoning and setbacks

(530) 458-0481

1213 Market Street, Colusa, CA 95932

Online permits →

Septic permits

Colusa County Environmental Health

Onsite wastewater treatment systems and water-well permits and inspections

(530) 458-0888

1213 Market Street, Colusa, CA 95932

Online permits →

Roads & driveways

Colusa County Public Works

County-road encroachment and transportation permits, flood control, roads and bridges

(530) 458-0466

1215 Market Street, Colusa, CA 95932

Floodplain permits

Colusa County Public Works — Floodplain Permits

Floodplain permits and flood elevation certificates

(530) 458-0466

Contact details are copied from each office’s official page and were checked against it on September 27, 2026.

Do you need a building permit in Colusa County, California?

Yes. Colusa County requires permits for new residential, commercial and industrial buildings, additions, decks, pools, water heaters, patio covers, conversions, expansions, reroofing, electrical and plumbing systems, heating and air-conditioning systems, and structures over 120 square feet; the county says that list is not exhaustive1. California's current statewide building standards apply to permit applications dated on or after January 1, 202612. After issuance, county inspectors verify that work matches the permit, applicable codes and approved plans13. At completion, the inspector signs the job card, and the county can issue a Certificate of Occupancy or Notice of Completion upon request14. An owner-builder option can exempt a qualifying owner from contractor licensing, but it does not remove the county permit or inspection requirements1115.

Who issues building permits in Colusa County, and how do you reach them?

The Colusa County Building Department receives building applications through the county's online permit portal and reviews project plans for code compliance16. The same coordinated review sends the plot plan to Planning for allowed-use and setback review, Environmental Health for wells and waste disposal, the applicable fire district for State Fire-Safe review, and Public Works for county-road encroachments, flood hazards and significant grading2. The Building Department is at 1213 Market Street in Colusa and can be reached at (530) 458-048116. A complete plan set may need electrical and plumbing plans, truss and energy calculations, a plot plan, and applicable sprinkler and solar plans2. The plot plan must also identify streets, easements and the access road17.

Does Colusa County have zoning?

Yes. Unincorporated Colusa County uses mapped zoning districts, and Planning reviews whether a proposed use is allowed and whether the plot plan meets setbacks316. County zoning maps cover the county and separately show Arbuckle, College City, Grimes, Maxwell, Princeton, Stonyford and Lodoga, plus unincorporated Colusa and Williams18. Rules vary by district: in the county's agricultural zones, agricultural structures have front setbacks of 20 or 25 feet, rear setbacks of 20 feet and side setbacks of 10 feet, while non-agricultural structures have 25-foot front and rear setbacks and side setbacks of 20 or 25 feet19. Maximum heights also differ by structure type and agricultural district20. The county materials do not confirm one minimum home size for every unincorporated parcel, so ask Planning to check the parcel's zoning district and proposed dwelling classification before design.

How do septic permits work in Colusa County?

Colusa County Environmental Health administers onsite wastewater treatment systems in unincorporated areas for ordinary systems designed at 10,000 gallons per day or less7. A permit is required before constructing, reconstructing or repairing a septic system, and site evaluation is part of approval8. Only 3.9% of county soils avoid a severe USDA limitation for a conventional drain field, so test the actual homesite early and budget for a design beyond a standard trench system if the evaluation requires one21. A property with an approved available sanitary sewer within 200 feet must connect when the right-of-way and required sewer-authority and LAFCO approvals can be obtained22. Surface-discharge approaches such as surface irrigation or evaporation ponds are not authorized as county OWTS, and alternative systems carry installation, operating, monitoring and inspection requirements23. Environmental Health is at 1213 Market Street in Colusa and can be reached at (530) 458-088824.

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

You cannot use an RV as a permanent residence in unincorporated Colusa County; temporary RV occupancy during home construction requires a Temporary Use Permit and must fit the circumstances allowed by county code9. The county materials reviewed do not confirm a general private-land camping allowance outside that construction pathway, so ask Planning before placing or occupying an RV. A park-trailer tiny home outside an approved mobile-home or special-occupancy park can qualify as an accessory dwelling unit only if utilities connect to county-approved systems under permit, the wheels and tongue are removed, a permitted county-approved foundation supports it, and its exterior and skirting meet the county's residential-design conditions10. More generally, California requires an occupied tiny home to qualify under an approved classification such as a code-built home, manufactured home, factory-built housing, RV or park trailer25.

Building a home in Colusa County: what are the steps?

  1. Ask Planning to verify the parcel's zoning district, allowed residential use, setbacks and any required land-use approval before finalizing plans16.
  2. Start the Environmental Health site evaluation and septic permit if public sewer is unavailable, because poor drain-field ratings make early soil work especially valuable821.
  3. Apply to Environmental Health before drilling, modifying or abandoning a water well5.
  4. Prepare the building plans and a plot plan showing buildings, utilities, sewage disposal, streets, easements and access217.
  5. Submit the complete building application through the online permit portal16.
  6. Coordinate with Public Works if the project affects county right-of-way, grading or a flood hazard, and obtain a Caltrans encroachment permit if access enters a state highway2627.
  7. Keep approved plans onsite and complete the required inspections through final sign-off13.

What should you check before buying land in Colusa County?

Have Planning confirm the exact zone, allowed dwelling type, setbacks and parcel status; county zoning is not one uniform rule, and a land division requires county subdivision review628. Check the flood map and ask Public Works about any floodplain permit or elevation-certificate requirement before choosing a building pad29. Verify legal access too: Public Works issues and inspects permits for work in county right-of-way, while access onto a state highway needs Caltrans approval2627. Water deserves equal attention because wells require a county permit and severe drought occurs in about 41% of years530. Septic feasibility is a major purchase contingency because only about 4% of soils avoid severe limits for a conventional drain field21. For carrying costs, the effective property-tax rate is about 0.7%, and the median annual bill is about $2,4813132.

Watch-outs

  • A shed or similar structure over 120 square feet is specifically listed as permit-required, but the county's list is not exhaustive; ask the Building Department before beginning smaller work too1.
  • Permanent RV residence is not allowed, and temporary occupancy during home construction requires a Temporary Use Permit9.
  • A nearby sewer can change the septic plan: qualifying structures within 200 feet of approved available sanitary sewer must connect when the ordinance's access and approval conditions are met22.
  • Public Works says county subdivision standards are being updated and may change before revised standards are posted, so confirm the current version before designing a land split28.

Sources

  1. Building Permits, quoted and re-checked
  2. Building Permits, quoted and re-checked
  3. Colusa County Code Chapter 44 Zoning (2026 county census)
  4. Colusa County Onsite Wastewater Treatment Systems Ordinance (2026 county census)
  5. Appendix G Drainage, Hydrology, and Water Quality Analysis, quoted and re-checked
  6. Zoning Code | Colusa County, CA, quoted and re-checked
  7. Colusa County Onsite Wastewater Treatment Systems Ordinance, quoted and re-checked
  8. Colusa County Onsite Wastewater Treatment Systems Ordinance, quoted and re-checked
  9. General Information Sheets, quoted and re-checked
  10. Ordinance No. 819 — Tiny Homes, quoted and re-checked
  11. Building Permit Form, quoted and re-checked
  12. Approved Building Standards (California statewide rule), quoted and re-checked
  13. Building Permits, quoted and re-checked
  14. Building Permits — Final Approval, quoted and re-checked
  15. Owner-Builder Responsibilities (California statewide rule), quoted and re-checked
  16. Colusa County Building Department (countyofcolusaca.gov)
  17. Building Permits, quoted and re-checked
  18. Zoning Code, quoted and re-checked
  19. Zoning Code, quoted and re-checked
  20. Zoning Code, quoted and re-checked
  21. Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
  22. Colusa County Onsite Wastewater Treatment Systems Ordinance, quoted and re-checked
  23. Colusa County Onsite Wastewater Treatment Systems Ordinance, quoted and re-checked
  24. Colusa County Environmental Health (countyofcolusaca.gov)
  25. Information Bulletin 2016-01: Tiny Homes (California statewide rule), quoted and re-checked
  26. Colusa County Public Works (countyofcolusaca.gov)
  27. Encroachment Permits | Caltrans (California statewide rule), quoted and re-checked
  28. Subdivision Standards, quoted and re-checked
  29. Colusa County Public Works — Floodplain Permits (countyofcolusaca.gov)
  30. Share of years in severe drought: Bolthole Index county data
  31. Effective property tax rate: Bolthole Index county data
  32. Median property tax bill: Bolthole Index county data

Written September 27, 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.

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County locator

Colusa County in California

44
County map
Colusa County highlighted among the California counties · colored by Index score

How Colusa County scores

Seclusion48100% ev.
Self-Sufficiency43100% ev.
Admin Boringness41100% ev.
Durability22100% ev.
Property Autonomy56100% ev.
Carry Cost56100% ev.

Evidence strength: 100%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$380kTypical home
0.7%Property tax
$11,119Land / acre
24.8"Annual rain
40.8% of yrsSevere drought
35.6 / yr (+20.8)Mid-century 100°F days
87.9 daysMid-century dry spell
1.56" (+6.8%)Mid-century 1-day rain
1.08×Wildfire change factor
100%Forward climate coverage
$1,239Home insurance / yr
2.2% / yrInsurance growth
1.06%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
17,055People within 30 min
5,313,539People within 2 hr
16,248Radius comparison (15 mi)
19.2People / sq mi
19.2%Federal land
61.4%Land at 15% slope or less
3.9%Septic soil without severe limits
28,138 acWorkable land screen
31.7%Wooded land
23 tonsBiomass / forest ac
61.6°FAvg temp

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Answers from the rulebook for Colusa County

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

Colusa County rules

  • Building permitRequired

    Construction work administered through the Colusa County Building Department.

    • The official handout states the listed permit-required activities are not exhaustive.
    • The source directs applicants to contact the Building Department to determine whether a permit is needed.
    • The listed examples include new residential, commercial, and industrial buildings; additions; residential work; renovations; electrical and plumbing systems; heating and air-conditioning systems; and structures over 120 square feet.

    structure area threshold: > 120 sq. ft. (The source states permits are required for any structure over 120 sq. ft.)

    “Permits are required for the following, but not limited to:  New buildings (Residential, Commercial & Industrial).  Addition(s) to existing structure  Residential work (decks, pools, water heaters, patio covers, etc.)  Renovations (conversions, expansions, re-roofing, etc.)  Electrical and Plumbing systems  Heating & Air Conditioning systems  Any structure over 120 sq. ft.”
  • Owner-builder exemptionConditional

    An owner applying for a Colusa County building permit and claiming exemption from the California Contractor's State License Law.

    • The declaration must be made under penalty of perjury.
    • The owner may perform the work personally or through employees whose wages are their sole compensation, but the structure must not be intended or offered for sale.
    • Alternatively, the owner may exclusively contract with licensed contractors.
    • The form also provides an option to identify another exemption under a specified Business and Professions Code section and reason.
    • The permit form separately requires workers' compensation declarations.
    “I hereby affirm under penalty of perjury that I am exempt from the Contractor's State License Law for the following reason: [ ] I, as owner of the property, or my employees with wages as their sole compensation, will do the work, and the structure is not intended or offered for sale. [ ] I, as owner of the property, am exclusively contracting with licensed contractors to construct the project.”
  • InspectionsRequired

    Projects for which Colusa County has issued a building permit.

    • On-site inspections are required to verify conformity with the permit, applicable codes, and approved plans.
    • The permit must be posted at the job site and project plans must be on site for the building inspector.
    • Inspection requests must be made two days before the inspection date according to the handout; the current inspection-information page requests inspections at least three to five days in advance.
    • The inspection-information page requires approved and stamped plans and specifications on site if applicable, the building permit number, and the building location.
    • Failure to comply with the current inspection-information requirements results in a $47-per-hour re-inspection fee, payable before another inspection is scheduled; additional fees may be charged under the county building code.

    inspection request lead time: 2 days (The official inspection-information webpage currently requests three to five days in advance.) · re-inspection fee: 47 USD per hour (Additional fees may be charged under the county building code.)

    “On-site inspections will be required to make certain the work conforms to the permit, appropriate codes and approved plans.”
  • Certificate of occupancyLimited

    Completed projects subject to Colusa County building inspection and final approval.

    • The building inspector must sign the project job card as complete, indicating compliance with code requirements.
    • A Certificate of Occupancy or a Notice of Completion is issued upon request, so the source does not establish a universal mandatory certificate requirement for every project.
    “At the completion of the project, the building inspector will sign the project job card as complete, indicating compliance with code requirements. A Certificate of Occupancy or a Notice of Completion will be issued upon request.”
  • Local zoningVaries (with conditions)

    Aggregate local zoning within Colusa County; zoning controls vary by mapped county zoning district and by incorporated or unincorporated community, rather than representing one uniform rule for every parcel.

    • This is an aggregate county claim and does not assert that the County administers each municipal ordinance.
    • The County states that its zoning ordinance directs land uses to specified lands and regulates intensity, structure location, parking, building height, and other development requirements.
    • The County's official zoning page separately identifies maps for Arbuckle, College City, Grimes, Maxwell, Princeton, Stonyford and Lodoga, and unincorporated Colusa and Williams.
    “Specific zoning districts separate land uses which might be incompatible with each other. Zoning does this by directing industrial, commercial, residential, and other land uses to specified lands where similar uses will be located.”
  • Zoning districtsPublished

    Colusa County zoning code and published zoning maps for county-regulated unincorporated areas.

    • The County page states that the zoning code was adopted on August 26, 2014.
    • Published maps include a countywide map and area maps for Arbuckle, College City, Colusa (Unincorporated), Grimes, Maxwell, Princeton, Stonyford and Lodoga, and Williams (Unincorporated).
    • Incorporated municipalities may administer their own land-use rules; this claim is limited to County-regulated areas.

    zoning code adoption date: August 26, 2014

    “Read Colusa County’s Zoning Code adopted on August 26, 2014.”
  • SetbacksDistrict specific (with conditions)

    Agricultural and non-agricultural structure setbacks in the county agricultural zoning districts F-A, E-A, U-C, U-T, and A-T in unincorporated Colusa County.

    • Agricultural-structure front setbacks are 25 feet in F-A, E-A, and U-C, and 20 feet in U-T and A-T.
    • Agricultural-structure rear setbacks are 20 feet in all five listed districts.
    • Agricultural-structure side setbacks are 10 feet in all five listed districts.
    • Non-agricultural-structure front and rear setbacks are 25 feet in all five listed districts.
    • Non-agricultural-structure side setbacks are 25 feet in F-A, E-A, and U-C, and 20 feet in U-T and A-T.
    • The zoning code states that allowed uses and associated structures must comply with the development standards unless a variance is obtained.

    agricultural structure front setback: 25 ft in F-A, E-A, U-C; 20 ft in U-T and A-T · agricultural structure rear setback: 20 ft · agricultural structure side setback: 10 ft · non-agricultural structure front setback: 25 ft · non-agricultural structure rear setback: 25 ft · non-agricultural structure side setback: 25 ft in F-A, E-A, U-C; 20 ft in U-T and A-T

    “Allowed uses and associated structures shall comply with the following development standards, in addition to any other applicable requirements of this Title, unless a variance is obtained in compliance with Section 44-1.80 (Types of Permits).”
  • Building heightDistrict specific (with conditions)

    Maximum structure heights in the county agricultural zoning districts F-A, E-A, U-C, U-T, and A-T in unincorporated Colusa County.

    • Maximum agricultural-structure height is 50 feet in all five listed districts.
    • Maximum accessory agricultural-structure height is 100 feet in F-A, E-A, and U-C, and 50 feet in U-T and A-T.
    • Maximum non-agricultural-structure height is 30 feet in all five listed districts.
    • The zoning code states that allowed uses and associated structures must comply with the development standards unless a variance is obtained.

    maximum agricultural structure height: 50 feet · maximum accessory agricultural structure height: 100 ft in F-A, E-A, U-C; 50 ft in U-T and A-T · maximum non-agricultural structure height: 30 feet

    “Maximum Height for Agricultural Structures 50 ft 50 ft 50 ft 50 ft 50 ft Maximum Accessory Agricultural Structure Height 100 ft 100 ft 100 ft 50 ft 50 ft Maximum Height for Non-Agricultural Structures 30 ft 30 ft 30 ft 30 ft 30 ft”
  • Living in an RVTemporary only (with conditions)

    Recreational-vehicle occupancy during home construction in unincorporated Colusa County.

    • Permanent residence in a recreational vehicle is not allowed.
    • Temporary occupancy requires a Temporary Use Permit and is available only under circumstances specified in the County Code.
    • The cited county page does not state the full conditions in the handout because the linked handout could not be retrieved.
    “You may not live in a recreational vehicle as a permanent residence. [...] you may occupy a Recreational Vehicle temporarily with a Temporary Use Permit.”
  • Tiny homesAllowed (with conditions)

    A tiny home park trailer located outside a county- and state-approved mobile-home or special-occupancy park, when used as an accessory dwelling unit in unincorporated Colusa County.

    • All utilities must be connected to county-approved systems under an issued county permit.
    • The wheels and tongue must be removed.
    • The structure must be supported by a county-approved foundation system for which a building permit has been issued.
    • The exterior must include typical residential design elements so that it resembles a residential structure and not a recreational vehicle, to the satisfaction of the Community Development Director.
    • Skirting must match or complement the exterior and screen the underside chassis and foundation system, to the satisfaction of the Community Development Director.
    “A Tiny Home ( Park Trailer) [...] is considered an approved type ofaccessory dwelling unit ifthe following criteria are met:”
  • Manufactured homesLimited

    Manufactured or mobile homes in the county residential zoning districts R-R, R-1, R-2, R-3, and R-4.

    • The zoning table identifies manufactured or mobile homes as permitted in all five listed residential zones.
    • Temporary mobile homes are separately identified as requiring a Temporary Use Permit under section 44-4.80.
    • Other development, building, foundation, utility, and applicable health requirements may apply.
    “Manufactured or Mobile Home P P P P P 44-4.70 Mobile Home (temporary) T T T T T 44-4.80”
  • Who permits septicCounty

    Existing and new onsite wastewater treatment systems in unincorporated Colusa County with wastewater design flow of 10,000 gallons per day or less.

    • For systems producing more than 10,000 gpd, systems receiving significant RV holding-tank waste, or systems with above-ground effluent discharge, treatment and dispersal must be approved by the Regional Water Quality Control Board.
    • The chapter does not apply within the jurisdictional limits of a governmental entity that has agreed with the Board of Supervisors to assume responsibility for regulating or issuing OWTS permits.
    • The Environmental Health Division director administers and enforces the chapter on behalf of the County Health Officer.

    maximum wastewater design flow: <= 10000 gpd (Systems exceeding this threshold require Regional Water Quality Control Board approval.) · RV holding-tank waste: significant amounts (Regional Water Quality Control Board approval required.) · above-ground effluent discharge: not covered by ordinary county OWTS administration (Regional Water Quality Control Board approval required.)

    “The director of the Environmental Health Division or his/her assign(s) , on behalf of the County’s Health Officer, shall administer and enforce all provisions of this Chapter relative to installation, maintenance, operation and abandonment of OWTS”
  • Septic permitRequired

    Construction, rebuilding, remodeling, repair, alteration, or replacement of an OWTS serving a residence, business, or other occupied building in unincorporated Colusa County.

    • Plans must be submitted to the Director for approval.
    • For a structure not connected to an approved sanitary sewer, approval of the proposed construction or an OWTS installation permit is required.
    • Permits are valid for one year from issuance and are nontransferable.
    • Applications must be submitted in writing to the Environmental Health Division with fees set by the current Board of Supervisors environmental-health fee resolution.
    • A site evaluation is required before permit approval, subject to the stated testing and waiver provisions.

    permit duration: 1 year (Renewal procedures apply if additional construction time is needed.) · sanitary sewer separation: > 200 feet (The manual states permits are issued only where sanitary sewer is not available within 200 feet.)

    “A permit must be obtained from the Colusa County Environmental Health Department (CCEH) to construct, reconstruct, or repair an onsite wastewater treatment and dispersal system.”
  • Off-grid sanitationLimited

    Off-grid sanitation using OWTS or alternative sanitation systems in unincorporated Colusa County.

    • OWTS may be used where authorized by Chapter 36 and the Onsite Systems Manual, subject to approval, siting, design, installation, inspection, and operating requirements.
    • Surface discharge systems, including surface irrigation, percolation ponds, or evaporation ponds, are not authorized under the County OWTS ordinance.
    • Chemical toilets require a permit except for temporary construction use; the Director may waive the requirement for other temporary activities if no health or safety issue is created.
    • Alternative OWTS require an installation permit and renewable operating permit with monitoring and inspection requirements.
    • Public sewer connection is required within 200 feet when the ordinance conditions are met.

    maximum ordinary county OWTS design flow: <= 10000 gpd (Higher flows require Regional Water Quality Control Board approval.)

    “Wastewater systems that discharge effluent above ground (e.g., via surface irrigation, percolation/evaporation pond) are not covered within the definition of an OWTS and are not authorized under this Chapter.”
  • Well permitRequired

    New wells, modifications to existing onsite supply wells, and well abandonment in Colusa County.

    • Applications are submitted through the County online portal.
    • County Water Wells page states drillers must notify the office 48 hours in advance for inspection.
    • The cited County project document describes these permits as ministerial rather than discretionary.

    advance inspection notice: 48 hours (Applies to drillers.) · domestic/private well fee: 364 USD (County Water Wells fee schedule; other well categories have separate fees.) · well abandonment/destruction fee: 168 USD (County Water Wells fee schedule.)

    “If any modifications are made to the existing onsite supply wells, if either well is to be abandoned, or if any new wells are to be drilled, then a permit would be required from the Colusa County Environmental Health Division within the Community Development Department.”
  • Mandatory utility hookupSewer (with conditions)

    Structures requiring sewage disposal in unincorporated Colusa County located within 200 feet of an approved available sanitary sewer.

    • Connection must be made in the most direct manner possible.
    • A right-of-way and necessary approval from the appropriate sewer authority and Colusa County LAFCO must first be obtained.
    • For existing OWTS, connection is required upon system failure or when major repair, septic-tank replacement, or an OWTS addition is required or proposed, if feasible and approved by the Director.

    distance to available sanitary sewer: <= 200 feet (Connection requirements are subject to feasibility, right-of-way, sewer-authority approval, and LAFCO approval.)

    “Every property where there is proposed a residence, place of business, or other building or place which people occupy, or where persons congregate, reside or are employed, and which proposed structures requiring sewage disposal are within two hundred (200) feet of an approved available sanitary sewer, must be connected to the sanitary sewer in the most direct manner possible, provided a right-of-way and any necessary approval from the appropriate sewer authority and the Colusa County Local Agency Formation Commission (LAFCO) can be first obtained.”
  • Subdividing landRegulated (with conditions)

    Subdivision and parcel-division applications in unincorporated Colusa County.

    • The county identifies its subdivision standards as current, but warns they may change before updates are posted.
    • Tentative parcel maps and tentative subdivision maps are submitted through the county land-use application process.
    • Applicants are directed to contact the Public Works Department to confirm additions, deletions, or changes to the standards.

    Public Works confirmation phone: 530-458-0466

    “The Subdivision Standards accessible on this page are the current standards for Colusa County. The county is in the process of updating the standards, and they may be subject to change prior to being posted.”
  • Driveway accessRequired

    Building permit plot plans for projects subject to Colusa County review in unincorporated areas.

    • The plot plan must show all streets and easements, identify streets, and show the location of the access road.
    • This claim establishes a documentation requirement for the building permit application, not a universal physical driveway-construction standard.
    “7. Show all streets and easements. Identify streets 8. Show the location of the access road”
  • Permit feesPublished

    Published Colusa County Public Works permit fees, including encroachment, transportation, land grading, and flood zone development permits.

    • The encroachment fee is 3% of the estimated cost of work within the County right of way.
    • The permittee is billed for County inspection costs on weekends and holidays.
    • The flood zone development permit has no fee.
    • The fee schedule identifies the cited encroachment fee as adopted under Resolution Number 84-31 and the land grading fee under Ordinance 414.

    encroachment permit fee: 3% of estimated cost of work within County right of way (Permittee billed for County costs for inspections on weekends and holidays.) · flood zone development permit fee: No Fee

    “Encroachment Permit: | 3% of the estimated cost of work within County right of way. Permittee billed for County costs for inspections on weekends and holidays. [Resolution Number 84-31]”
  • Permit processPublished (with conditions)

    County building permit applications handled through Colusa County's online permit portal.

    • All permit applications must be submitted through the Online Permit Portal.
    • Planning reviews setback requirements and whether the proposed use is allowed in the assigned zone.
    • Building reviews project plans and code compliance.
    • Environmental Health reviews well and waste-disposal matters.
    • Depending on location, the fire district reviews State Fire-Safe compliance.
    • Public Works reviews road encroachments, flood hazards, and significant grading.
    • Required materials include electrical and plumbing plans, truss calculations, energy calculations, a plot plan, and when applicable sprinkler and solar plans.
    “ALL Permit Applications must be submitted through the Online Permit Portal.”
  • County-wide zoningPresent

    Colusa County Code Chapter 44 (Zoning Code) assigns zoning districts to unincorporated parcels; the Planning Department reviews allowed uses and setbacks.

    Colusa County Code Chapter 44 Zoning ↗Scouted from the county site, not yet independently re-checked

California rules that apply here

  • Building code adoptedAdopted (with conditions)

    California Building Standards Code, California Code of Regulations, Title 24, including the 2025 California Building Code and related parts, for buildings and structures subject to the state code.

    • The 2025 California Building Standards Code applies to buildings and structures with a permit application date on or after January 1, 2026.
    • The applicable local building department or enforcing agency determines how the permit application date is established in a specific jurisdiction.
    • The code includes multiple parts, including the California Building Code, California Residential Code, Existing Building Code, Electrical Code, Mechanical Code, Plumbing Code, Energy Code, Wildland-Urban Interface Code, Fire Code, and Green Building Standards Code.

    effective date: 2026-01-01 · permit application date: >= 2026-01-01

    “The 2025 California Building Standards Code (CBSC), California Code of Regulations (CCR), title 24, will become effective on January 1, 2026, as a result of the 2024 Triennial Code Adoption Cycle. [...] The 2025 CBSC applies to all buildings and structures with a permit application date on or after January 1, 2026.”
    One more reviewed finding on this topic
    • Adopted — California statewide building standards, including residential construction subject to Title 24 of the California Code of Regulations.
      “Except as otherwise specifically provided by law, the building standards adopted and submitted by the department for approval [...] shall be adopted by reference”
  • Minimum dwelling sizeSpecified

    Efficiency units permitted by a California city, county, or city and county.

    • The local jurisdiction must adopt an ordinance permitting the efficiency unit.
    • Occupancy is limited to no more than two persons.
    • The unit may have partial kitchen or bathroom facilities as specified by the local ordinance.
    • All other applicable minimum standards under Health and Safety Code Part 1.5 continue to apply.

    minimum floor area: >= 150 square feet · maximum occupancy: <= 2 persons

    “Notwithstanding Sections 17922, 17958, and 17958.5, a city, county, or city and county may, by ordinance, permit efficiency units for occupancy by no more than two persons which have a minimum floor area of 150 square feet and which may also have partial kitchen or bathroom facilities, as specified by the ordinance.”
  • Camping on your landLimited

    Camping in units operated by the California Department of Parks and Recreation statewide.

    • Camping is confined to areas designated for that purpose.
    • Occupancy by the same persons, equipment, or vehicles is generally limited to 30 days in any calendar year in that unit.
    • The Department may establish shorter or longer occupancy limits.
    • When a shorter seasonal limit applies, the camper must vacate the campsite and may not reregister in the unit until 48 hours have expired, measured from 12:00 noon on the checkout day to 12:00 noon on the second day following.
    • A district superintendent may permit one-night camping in a day-use area or portion of one, subject to Department-established fees and vehicle limitations; occupants must vacate by 9:00 a.m. the following morning.
    • California State Parks' current reservation policy states that each campground has a consecutive-night limit, requires a 48-hour absence after that limit, and generally has a 30-night annual maximum, subject to individual park policies.

    general annual occupancy limit: 30 days per calendar year per unit (The Department may establish shorter or longer limits of occupancy.) · return interval after shorter seasonal limit: 48 hours (Measured from 12:00 noon of the checkout day to 12:00 noon of the second day following.) · one-night camping in day-use area: 1 night (Only if permitted by the district superintendent; occupants must vacate by 9:00 a.m. the following morning.)

    “Occupancy by the same persons, equipment, or vehicles of any camping facility is limited to a total of 30 days in any calendar year in that unit.”
    One more reviewed finding on this topic
    • Allowed (with conditions) — Temporary camping in California special occupancy parks, including parks containing recreational vehicles, tents, or camping cabins.
      ““Special occupancy park” means a recreational vehicle park, temporary recreational vehicle park, incidental camping area, or tent camp.”
  • Accessory dwellingsAllowed (with conditions)

    ADUs and junior ADUs subject to California State ADU Law.

    • Approval is ministerial and without discretionary review or a hearing.
    • Development standards must be objective and knowable in advance.
    • The local permitting agency must determine application completeness and provide written notice within 15 business days.
    • If an application is incomplete, the agency must identify missing items and explain how to complete it.
    • Local site, building, health, safety, fire, utility, and other applicable requirements continue to apply.

    written completeness determination: <= 15 business days (Measured from the permitting agency's receipt of the application.) · final written determination after appeal: <= 60 business days (Applies after receipt of the written appeal.)

    “A permit application for an accessory dwelling unit shall be considered and approved ministerially without discretionary review or a hearing [...] A permitting agency shall determine whether an application to create or serve an accessory dwelling unit is complete and provide written notice of this determination to the applicant not later than 15 business days after the permitting agency received the application.”
  • Septic inspectionLimited

    OWTS in a Tier 3 Advanced Protection Management Program with supplemental treatment components, including systems in specified impaired-water-body areas statewide.

    • The requirement applies to OWTS in an Advanced Protection Management Program with supplemental treatment components.
    • Ongoing monitoring must follow the OWTS operation and maintenance manual or occur more frequently if required by the local agency or Regional Water Board.
    • Where telemetry is not possible, the owner or owner's agent must inspect at least monthly while the system is in use and notify the service provider at least quarterly of observed operating parameters.
    • For systems designed to meet disinfection requirements, a service provider must inspect proper operation quarterly while the system is in use unless continuous telemetric monitoring is capable of assessing operation.
    • Quarterly effluent sampling and certified-laboratory requirements apply to systems subject to the disinfection provisions.

    inspection frequency where telemetry is not possible: per monthly (While the system is in use.) · inspection frequency for disinfection systems: per quarterly (While the system is in use, unless continuous telemetric monitoring is capable of assessing operation.)

    “Where telemetry is not possible, the owner or owner’s agent shall inspect the system at least monthly while the system is in use as directed and instructed by a service provider and notify the service provider not less than quarterly of the observed operating parameters of the OWTS. [...] OWTS in an Advanced Protection Management Program designed to meet the disinfection requirements in Section 10.10 shall be inspected for proper operation quarterly while the system is in use by a service provider unless a telemetric monitoring system is capable of continuously assessing the operation of the disinfection system.”
  • Campground & park staysLimited

    Occupancy and use of manufactured homes and mobilehomes in California mobilehome parks and other locations subject to HCD jurisdiction.

    • HCD administers titling and registration for manufactured homes and mobilehomes.
    • HCD-inspected mobilehome parks are subject to health and safety enforcement where local government has not assumed enforcement.
    • Manufactured/mobilehome park regulations address construction, use, maintenance, and occupancy.
    • Separate local land-use, building, fire, health, and utility requirements may apply.
    “MHs may be occupied outside or inside of mobilehome parks and installation and approval for occupancy is governed by the Mobilehome Parks Act (MPA), HSC Sections 18200, et seq., and Title 25, CCR Sections 1000, et seq.”
    2 more reviewed findings on this topic
    • Limited — RV and trailer camping at Silver Strand State Beach Campground in the San Diego Coast District.
      “Camping Stay Limits: Applies to persons, equipment, or vehicles and any combination thereof [...] Maximum stay of 30 days per calendar year [...] Maximum 7 consecutive days during peak season (May 15 – September 15) [...] Maximum 14 consecutive days during non-peak season”
    • Limited — Occupancy and use of recreational vehicles in California special occupancy parks and designated RV sections of mobilehome parks.
      “Unless otherwise allowed by a local ordinance, RVs generally may be occupied only in mobilehome parks or special occupancy parks governed by the Mobilehome Parks Act”
  • county zoning authorityGeneral

    California county legislative bodies' authority to adopt zoning ordinances regulating buildings, structures, land uses, lots, yards, open space, lot coverage, intensity of use, parking, loading, and setbacks within county jurisdiction, including unincorporated areas.

    • The authority is exercised pursuant to Government Code Chapter 4, Zoning Regulations.
    • The statute separately authorizes city legislative bodies; incorporated municipalities may exercise their own zoning authority.
    • Government Code Section 65850 also lists authority to regulate signs and billboards, building and structure location, height, bulk, number of stories, and size, lot and open-space size and use, lot coverage, intensity of land use, offstreet parking and loading, and building setback lines.
    • The cited section states it was amended by Stats. 2017, Ch. 376, Sec. 1, effective January 1, 2018.
    “The legislative body of any county or city may, pursuant to this chapter, adopt ordinances that do any of the following:”
  • county building authorityGeneral

    California counties administering and enforcing state building standards through county building departments, including residential construction in unincorporated areas.

    • Each county must maintain building standards and state building regulations in the office of the building official responsible for administration and enforcement of state building standards.
    • The statewide Title 24 standards apply subject to statutory exceptions and any authorized local amendments or local requirements.
    • The cited HCD bulletin concerns the 2019 California Building Standards Code and its July 1, 2021 supplement; later code editions may supersede those particular edition dates.
    “These codes shall be maintained in the office of the building official responsible for the administration and enforcement of state building standards”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

  • Lot coverage — Maximum lot coverage in unincorporated Colusa County.
  • Agricultural exemption — Potential agricultural exemptions from county zoning, building-permit, or related development requirements in unincorporated Colusa County.
  • Short-term rentals — Short-term or vacation rentals in unincorporated Colusa County.

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Water rights & wells in Colusa County

Whether a new home can legally get its own water here — the sub-state groundwater regime, from California’s water agency.

Actively managed

This basin is under active state management — new water use is scrutinized, though a domestic well is usually still allowed.

Household wellPermit required — restricted

California requires no STATE permit for a domestic well — wells are permitted by the county — but under SGMA a Groundwater Sustainability Agency can meter or restrict new wells in medium/high-priority and critically overdrafted basins, and Executive Order N-7-22 requires counties in those basins to get GSA verification that a new well is consistent with the Groundwater Sustainability Plan before permitting.

Limit: 2 acre-feet/year de minimis under SGMA (Water Code §10721(e)) — largely exempt from GSA metering/fees

California DWR / State Water Board — SGMA de minimis & EO N-7-22 Action 9 FAQ ↗
  • Sacramento Valley high-priority subbasinspartial of county

    High-priority SGMA subbasins (Corning, Colusa, Vina, Antelope-Tehama, South Yuba, North & South American, Solano, Yolo) with adopted GSPs; a new well is subject to GSA/EO N-7-22 consistency review.

    California DWR — SGMA Basin Prioritization ↗

Hybrid state (appropriation + riparian). Groundwater rules change and basin boundaries follow the aquifer, not the county line — confirm current well and appropriation rules with the California state water agency before you buy or drill.Groundwater governance as of Jul 2026, cited to each administering agency.

Living off-grid in Colusa County, California

Is Colusa County a good place to live off-grid or homestead?

Colusa County scores 44/100 on the Bolthole Index, a marginal county profile. Watch-outs: elevated mid-century heat, water, rain, or wildfire exposure and more administrative friction around building and land use.

Do you need a building permit in Colusa County, California?

Colusa County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Colusa County Environmental Health Division. Owner-builders may act as their own contractor to build their home. These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

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

Living in an RV on your own land in Colusa County is allowed on a temporary basis only: Recreational-vehicle occupancy during home construction in unincorporated Colusa County. Permanent residence in a recreational vehicle is not allowed. Temporary occupancy requires a Temporary Use Permit and is available only under circumstances specified in the County Code. A tiny home is allowed. Confirm with the county before relying on it.

How much does land cost in Colusa County, California?

Land in Colusa County runs about $11,119 per acre, based on the latest county data.

What is the water situation in Colusa County?

Colusa County gets about 24.8" of rain a year, with severe drought in roughly 40.8% of years. On water rights, Colusa County lies in the Sacramento Valley high-priority subbasins — High-priority SGMA subbasins (Corning, Colusa, Vina, Antelope-Tehama, South Yuba, North & South American, Solano, Yolo) with adopted GSPs; a new well is subject to GSA/EO N-7-22 consistency review..

How remote is Colusa County?

A representative private-land location has about 17,055 people within a 30-minute drive and 5,313,539 within two hours. The road-network catchments count population across county lines and clusters of smaller cities; straight-line radius values remain available as a comparison.

Off-grid gear

Going off-grid in Colusa County means bringing your own water and power. The kit we’d start with:

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How Colusa compares in California

Compare side-by-side →See all 58 California counties ranked →