Bolthole Index

Contra Costa County, California

Building permits, zoning and land rules in Contra Costa County, California

27Index Score / 100
#49 of 58 in California

Unincorporated Contra Costa County, California requires building permits, although narrowly defined work is exempt1. County zoning also applies, and the rules for a particular parcel depend on its zoning district23. Contra Costa Health handles onsite wastewater permits, while building applications and plans go through the county's digital ePermits system45.

At a glance

Building permit
Required in unincorporated areas; narrowly defined exemptions apply1
Zoning
County zoning applies to unincorporated parcels; cities administer their own zoning6
Septic permit
Handled by Contra Costa Health's Environmental Health Division4
RV living
Sleeping in an RV is prohibited in unincorporated areas except under specific code-authorized uses7
Tiny home
Not recognized as a separate planning category; wheels are treated as an RV8
Owner-builder
Available conditionally, but not an exemption from permits or inspections910
Private well
A local permit is required before construction, modification or destruction11
Septic soil suitability
Only 0.5% of mapped soil is free of severe limits for a conventional drain field12

Who to call

Building permits

Contra Costa County Department of Conservation and Development - Building Inspection

Building, grading and related permits and inspections for unincorporated Contra Costa County

925-655-2700

30 Muir Road, Martinez, CA 94553

Online permits →

Zoning

Contra Costa County Department of Conservation and Development - Planning Division

Zoning, planning applications and land-use review for unincorporated Contra Costa County

925-655-2774

30 Muir Road, Martinez, CA 94553

Online permits →

Septic permits

Contra Costa Health - Environmental Health Division

Septic construction permits, well permits, and site and soil evaluations through the Land Use Program

925-608-5500

2120 Diamond Boulevard, Suite 100, Concord, CA 94520

Floodplain permits

Contra Costa County Public Works Department - Floodplain Management Program

Floodplain permits and flood-hazard review for unincorporated Contra Costa County

925-655-2700

Roads & driveways

Contra Costa County Public Works Department - Encroachment Permits

Encroachment-permit questions for work affecting county roads

925-313-2000

Contact details are copied from each office’s official page and were checked against it on September 29, 2026.

Do you need a building permit in Contra Costa County, California?

Yes. Unincorporated Contra Costa County requires permits for regulated building work, but narrowly defined exemptions include qualifying one-story detached accessory structures no larger than 120 square feet and fences no higher than 7 feet1. Electrical, plumbing and mechanical work still requires a permit, and permit-exempt construction must comply with other laws1. Unincorporated Contra Costa County uses current California building codes along with the county code, while projects inside cities may also be governed by city ordinances13. An owner-builder may pull a permit only after completing the county acknowledgement; the owner remains legally and financially responsible and still needs required permits and inspections910. Building-permit fees vary with project valuation, while planning fees begin with an application-based deposit and may add time-and-materials charges14.

Who issues Contra Costa County building permits, and how do you reach them?

The Contra Costa County Department of Conservation and Development handles building permits and planning applications for unincorporated property from its permit center at 30 Muir Road in Martinez1516. Call the Application and Permit Center at 925-655-2700 for building questions or the Planning Division at 925-655-2774 for zoning and land-use questions1516. Contra Costa County requires building applications and plans to be filed digitally through the ePermits system; paper applications and plans are no longer accepted5. Larger projects require a plan-check fee before review begins5. Septic and well matters go to Contra Costa Health's Environmental Health Division at 925-608-5500, rather than the building counter17. Public Works answers encroachment-permit questions at 925-313-200018.

Does Contra Costa County have zoning?

Yes. Contra Costa County's Current Planning division administers zoning, subdivisions and land-use applications for unincorporated property219. Incorporated cities administer their own rules: Richmond has city zoning and subdivision regulations, while Concord provides its own zoning and development standards2021. For unincorporated land, identify the district and any planned-unit or specific-plan rules before relying on a listing3. Standards can vary sharply even within one area: Montalvin Manor's P-1 table has different minimum lot sizes, lot-coverage limits and building heights by district or use column222324. Contra Costa County has not published a generally applicable minimum dwelling size for every unincorporated residential parcel, so ask the Planning Division for the parcel's standards16.

How do septic permits work in Contra Costa County?

Contra Costa Health's Environmental Health Division administers permits for onsite wastewater treatment systems, including septic systems, vault privies and sewage holding tanks4. California's statewide wastewater policy allows local agencies to issue septic permits and use locally tailored siting and design standards25. Only 0.5% of Contra Costa County's mapped soils are rated free of severe limitations for a conventional septic drain field, so a site and soil evaluation should happen before a buyer relies on a standard system12. Call Environmental Health at 925-608-5500 to discuss the parcel and application17. A private well is separate: California requires a permit from the applicable local environmental-health agency or water district before a well is constructed, modified or destroyed11. Water and sewer connections can also depend on the sanitary district or public water provider serving the parcel, so ask Environmental Health and the identified utility before closing17.

Can you live in an RV or tiny home in Contra Costa County?

Human habitation, including sleeping, in an RV or travel trailer is prohibited in unincorporated Contra Costa County unless a specific county-code exception applies7. Exceptions include lawful mobile-home or travel-trailer parks and permitted RV parks or campgrounds in listed zoning districts; merely storing an RV at a residence does not authorize anyone to live or sleep in it7. Contra Costa County does not recognize "tiny home" as a separate planning category, treats a tiny home on wheels as an RV, and does not allow that vehicle to be permanently used as a mobile home8. A tiny structure may instead qualify through an approved building type or as an accessory dwelling unit, but that pathway requires planning and building approvals, plus Environmental Health review on septic-served property26. Ask the Planning Division which exception or approval path, if any, fits the parcel before placing or occupying an RV16.

What are the steps to build a home in Contra Costa County?

  1. Confirm that the parcel is unincorporated, then ask the Planning Division for its zoning district, allowed residential use, setbacks and any special-plan standards616.
  2. Determine water and wastewater service; if septic is needed, begin the Environmental Health site, soil and design review before fixing the house location417.
  3. Check flood and drainage constraints; improvements in a FEMA Special Flood Hazard Area require a Public Works floodplain permit, and new or substantially improved structures there require an elevation certificate27.
  4. Resolve legal road access and ask Public Works whether the proposed driveway work needs an encroachment permit18. A connection within a state-highway right of way requires a Caltrans encroachment permit28.
  5. Submit the building application and plans through ePermits, pay the required plan-check charge when applicable, and complete the county's final-inspection process before occupancy529. An occupancy certificate is specifically documented as conditional for covered multifamily rehabilitation projects, not as a separate document issued for every project30.

What should you check before buying land in Contra Costa County?

Start with jurisdiction and zoning: county zoning information covers unincorporated areas only, while a city parcel follows that city's rules6. Check septic feasibility early because only 0.5% of mapped county soils are rated free of severe limitations for a conventional drain field12. Review slope as well: 48.5% of county land is at a slope of 15% or less, so many parcels may bring grading or access complications31. Confirm whether the building area lies in a FEMA Special Flood Hazard Area, because covered improvements need a floodplain permit and new or substantial improvements require an elevation certificate27. If rental income matters, unincorporated short-term rentals require a permit and are restricted by zoning, hosting arrangement and operating standards32. Ask the applicable water provider or well-permitting authority about a reliable supply because no universal countywide connection rule was confirmed17. Finally, budget for property taxes: the effective rate is about 0.8%, and the median annual bill is about $6,9033334.

Watch-outs

  • Sleeping in an RV or travel trailer is prohibited in unincorporated Contra Costa County unless a specific code exception applies7.
  • Only 0.5% of Contra Costa County's mapped soil is rated free of severe limitations for a conventional septic drain field, so verify a usable wastewater site before buying12.
  • Construction in a FEMA Special Flood Hazard Area requires a floodplain permit, and new or substantial improvements also require an elevation certificate27.

Sources

  1. Construction Work Not Requiring a Building Permit, quoted and re-checked
  2. Planning and Zoning, quoted and re-checked
  3. Planning and Zoning, quoted and re-checked
  4. City and Agency Directory, quoted and re-checked
  5. Building permit Applications, quoted and re-checked
  6. Planning and Zoning, quoted and re-checked
  7. Code Enforcement, quoted and re-checked
  8. TINY HOMES, quoted and re-checked
  9. Owner-Builder Acknowledgement and Verification of Information, quoted and re-checked
  10. Owner-Builder Responsibilities (California statewide rule), quoted and re-checked
  11. Well Standards (California statewide rule), quoted and re-checked
  12. Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
  13. Current Building Codes, Ordinances & Technical Guidelines for Building Design, quoted and re-checked
  14. Payment Information, quoted and re-checked
  15. Contra Costa County Department of Conservation and Development - Building Inspection (contracosta.ca.gov)
  16. Contra Costa County Department of Conservation and Development - Planning Division (contracosta.ca.gov)
  17. Contra Costa Health - Environmental Health Division (cchealth.org)
  18. Contra Costa County Public Works Department - Encroachment Permits (contracosta.ca.gov)
  19. Planning and Zoning, quoted and re-checked
  20. Zoning & Subdivision Regulations, quoted and re-checked
  21. Land Use & Zoning Information, quoted and re-checked
  22. Montalvin Manor P-1 Development Guidelines, quoted and re-checked
  23. Montalvin Manor P-1 Development Guidelines, quoted and re-checked
  24. Montalvin Manor P-1 Development Guidelines, quoted and re-checked
  25. Onsite Waste Water Treatment Systems (California statewide rule), quoted and re-checked
  26. Accessory Dwelling Units, quoted and re-checked
  27. FEMA Floodplain Management Program, quoted and re-checked
  28. Encroachment Permits | Caltrans (California statewide rule), quoted and re-checked
  29. Permits by Department, quoted and re-checked
  30. Contra Costa County Multi-Family Housing Rehabilitation Standards, quoted and re-checked
  31. Share of land at 15% slope or less: Bolthole Index county data
  32. Short-Term Rentals, quoted and re-checked
  33. Effective property tax rate: Bolthole Index county data
  34. Median property tax bill: Bolthole Index county data

Written September 29, 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

Contra Costa County in California

27
County map
Contra Costa County highlighted among the California counties · colored by Index score

How Contra Costa County scores

Seclusion9100% ev.
Self-Sufficiency4696% ev.
Admin Boringness41100% ev.
Durability30100% ev.
Property Autonomy56100% ev.
Carry Cost51100% ev.

Evidence strength: 99%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$787kTypical home
0.8%Property tax
$9,199Land / acre
19.3"Annual rain
40.4% of yrsSevere drought
13.2 / yr (+8.4)Mid-century 100°F days
97.4 daysMid-century dry spell
1.51" (+7.9%)Mid-century 1-day rain
1.07×Wildfire change factor
100%Forward climate coverage
$1,682Home insurance / yr
5.7% / yrInsurance growth
0.73%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
599,339People within 30 min
12,666,427People within 2 hr
815,147Radius comparison (15 mi)
1,611.1People / sq mi
2.1%Federal land
48.5%Land at 15% slope or less
0.5%Septic soil without severe limits
1,718 acWorkable land screen
45.3 tonsBiomass / forest ac
60.4°FAvg temp

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Answers from the rulebook for Contra Costa County

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

Contra Costa County rules

  • Building permitRequired

    Building, structure, equipment, and other work regulated by Contra Costa County Ordinance 72-6.202 in unincorporated Contra Costa County.

    • The source states that permits are not required for one-story detached accessory structures not exceeding 120 square feet; Planning Division, Sanitary District, or Contra Costa County Environmental Health approval may still be required depending on location, and electrical, plumbing, and mechanical work requires a permit.
    • Fences not over 7 feet high are exempt; concrete and masonry walls are treated as walls and require permits.
    • Oil derricks are exempt.
    • Retaining walls not more than 3 feet high are exempt only when the stated 1:10 downward-slope condition is met and no listed surcharge, ground-slope, or Class I, II, or III-a liquid impoundment condition applies.
    • Water tanks supported directly on grade are exempt only when capacity is not greater than 5,000 gallons and height-to-diameter or width ratio does not exceed 2:1.
    • Sidewalks and driveways not more than 30 inches above adjacent grade are exempt only when they are not over a basement or story below and are not part of an accessible route; public sidewalk or driveway curb-cut repair or replacement requires Public Works review and approval.
    • Painting, papering, tiling, carpeting, cabinets, countertops, and similar finish work are exempt; the source advises contacting Building Inspection for clarification of cabinets, remodels, and additions.
    • Temporary motion-picture, television, and theater stage sets and scenery are exempt.
    • Prefabricated swimming pools accessory to Group R-3 occupancy are exempt only when less than 24 inches deep, not greater than 5,000 gallons, and installed entirely above ground; a protective barrier is required if water depth exceeds 18 inches.
    • Shade cloth structures constructed for nursery or agricultural purposes are exempt, excluding service systems.
    • Swings and other playground equipment accessory to detached one- and two-family dwellings are exempt.
    • Window awnings in Group R-3 and U occupancies are exempt only when supported by an exterior wall, projecting no more than 54 inches, and requiring no additional support.
    • Nonfixed and movable fixtures, cases, racks, counters, and partitions not over 5 feet 9 inches high are exempt.
    • Decks pertinent to R-3 and U occupancies are exempt only when not exceeding 200 square feet, not more than 30 inches above grade at any point, not attached to a dwelling, and not serving the code-required exit door.
    • The source states that permit exemptions do not authorize work violating the building code or other laws or ordinances.
    • The exemption document cites the 2022 California Residential Code; the County's current building-code page separately lists the 2025 California Building Code and County Code Title VII.

    detached accessory structure floor area threshold: <= 120 square feet (one-story detached accessory structure) · fence height threshold: <= 7 feet (concrete and masonry walls are not fences) · retaining wall height threshold: <= 3 feet (subject to slope, surcharge, ground-slope, and liquid-impoundment conditions) · water tank capacity threshold: <= 5000 gallons (supported directly on grade and height-to-diameter or width ratio no more than 2:1) · sidewalk or driveway elevation threshold: <= 30 inches (not over basement/story below and not part of accessible route) · prefabricated pool depth threshold: < 24 inches (Group R-3 accessory pool, not over 5,000 gallons, entirely above ground) · prefabricated pool capacity threshold: <= 5000 gallons (Group R-3 accessory pool, less than 24 inches deep and entirely above ground) · window awning projection threshold: <= 54 inches (Group R-3 or U occupancy, exterior-wall supported, no additional support) · movable fixture or partition height threshold: <= 5 feet 9 inches (nonfixed and movable fixtures, cases, racks, counters, and partitions) · deck area threshold: <= 200 square feet (R-3 or U occupancy, not attached to dwelling, not over 30 inches above grade, and not serving required exit door) · deck height threshold: <= 30 inches (R-3 or U occupancy and other deck conditions apply)

    “without first obtaining the necessary permits from the county building official.”
    One more reviewed finding on this topic
    • Required — Building construction and related work under Contra Costa County building-permit jurisdiction, particularly unincorporated areas.
      “Almost all projects require permits. These include, but are not limited to, new structures, demolitions, additions, alterations, interior/exterior remodels, running new electrical, water or gas lines, repairs, outdoor kitchens, pergolas, pavilions, decks, carports, garages, docks, pools, foundation repairs, ADUs, and Junior ADUs, solar, energy storage systems, and backup generators.”
  • Owner-builder exemptionConditional

    Property owners seeking to obtain a Contra Costa County building permit as owner-builders.

    • Owner-builders, including trusts or corporations, may pull permits.
    • Proof of ownership may be required.
    • The Building Permit Declaration form is required.
    • Before permit issuance, the property owner must complete and submit the Owner-Builder Acknowledgement and Verification form; an agent may not execute it.
    • The owner-builder is the responsible party of record and legally and financially responsible for the proposed construction.
    • If the owner employs persons other than California licensed contractors and construction value is at least $500 including labor and materials, the owner may be considered an employer.
    • An owner-builder building single-family residential structures cannot legally build them with intent to offer them for sale unless all work is performed by licensed subcontractors and the number of structures does not exceed four within a calendar year, or all work is performed under contract with a licensed general building contractor.
    • This is an owner-builder permit pathway, not an exemption from obtaining a building permit.

    construction value threshold for possible employer status: >= 500 USD (including labor and materials)

    “We will not issue a building permit until you have read, initialed your understanding of each provision, signed, and returned this form to us at our official address:”
    One more reviewed finding on this topic
    • Available (with conditions) — An owner-builder applying for a County building permit for property improvements in the County building-permit service area.
      “We will not issue a building permit until you have read, initialed your understanding of each provision, signed, and returned this form to us”
  • Building code adoptedAdopted (with conditions)

    Building construction in unincorporated Contra Costa County subject to the County Building Inspection Division's listed codes and ordinances.

    • The listed current codes include the 2025 California Building Standards Administrative Code Part 1, 2025 California Building Code Parts 2 Volumes 1 and 2, 2025 California Residential Code Part 2.5, California Electrical, Mechanical, Plumbing, Energy, Wildland-Urban Interface, Historical, Fire, Existing Building, Green Building, and Reference Standards Codes.
    • Contra Costa County Code Title VII also applies.
    • City ordinances apply depending on the city where the property is located, so incorporated-city requirements are not treated as County-only rules.
    • The source document states 'Updated 01/02/2026'; this is treated as a document update date, not as an effective or adoption date.
    “Current Building Codes & Ordinances • 2025 California Building Standards Administrative Code Part 1”
  • Certificate of occupancyLimited

    County-administered multifamily housing rehabilitation projects covered by the Contra Costa County Multi-Family Housing Rehabilitation Standards.

    • The source applies to properties assisted through Contra Costa County's Multi-family Housing Program.
    • The occupancy certificate is required only when required by the applicable project or building requirements.
    • Final disbursement is withheld until cited deficiencies and lead-based paint hazards are corrected and, when required, the building inspector has issued an occupancy certificate.
    • The standards incorporate the current edition of the International Building Code as adopted by Contra Costa County, with the more stringent standard applying where there is a conflict.
    “when required, the building inspector has issued an occupancy certificate.”
    One more reviewed finding on this topic
    • Limited — County building-permit projects requiring a final inspection and certificate-of-occupancy process.
      “Final Inspection (Certificate of Occupancy)”
  • County-wide zoningPresent (with conditions)

    Land-use entitlement and zoning review for proposed development on properties in unincorporated Contra Costa County.

    • The County Current Planning division reviews rezoning, subdivision, land-use, development-plan, tree-permit, and variance applications.
    • Applications must conform to local and relevant state regulations and CEQA.
    • The source identifies the scope as properties located within unincorporated Contra Costa County.
    “The division is also responsible for updating the County's zoning code.”
  • Local zoningVaries (with conditions)

    Aggregate conclusion for local zoning across Contra Costa County: County zoning applies in unincorporated areas, while incorporated municipalities administer their own zoning regulations.

    • The County source expressly limits County zoning information and Current Planning jurisdiction to unincorporated areas.
    • Municipal zoning is administered by the relevant city rather than by Contra Costa County.
    • A parcel-specific determination requires identifying whether the property is in an unincorporated area or an incorporated municipality and then consulting the applicable zoning district and standards.
    “Note the general plan and zoning information is available for unincorporated County areas only.”
  • Zoning districtsPublished (with conditions)

    County zoning districts and area-wide planned unit development codes in unincorporated Contra Costa County.

    • County zoning information is available for unincorporated County areas only.
    • The County provides a zoning code, area-wide P-1 zoning codes, a zoning map through CCMAP, and specific plans.
    • The listed unincorporated areas with P-1 zoning codes are Bay Point, Contra Costa Centre, El Sobrante, Montalvin Manor, North Richmond, and Rodeo.
    • The listed areas with specific plans are Alhambra Valley, Dougherty Valley (San Ramon), El Sobrante, Contra Costa Centre, Montalvin Manor, North Gate, North Richmond, Pittsburg/Bay Point BART Station Area, Rodeo, and Shell Ridge.
    • Incorporated cities administer their own zoning rules; this claim does not assign municipal zoning to the County.
    “Zoning Code - Including Area-Wide Planned Unit Developments (P-1). [...] Note the general plan and zoning information is available for unincorporated County areas only.”
  • Minimum lot sizeDistrict specific (with conditions)

    Minimum lot area in the unincorporated Montalvin Manor P-1 development-standard districts shown in the County guideline table.

    • The table contains multiple land-use/zoning columns; the applicable minimum depends on the specific district/use column.
    • The source does not identify a single countywide minimum lot size.
    • The County Planning page identifies Montalvin Manor as an unincorporated area with P-1 zoning codes.

    minimum lot area: 3,500 sq. ft.; 6,000 sq. ft.-7,000 sq. ft.; 3,500 sq. ft.; 5,000 sq. ft.; 2,500 sq. ft.; N/A; N/A square feet (varies by table column)

    “Minimum Lot Area 3,500 sq. ft 6,000 sq. ft-7,000 sq. ft 3,500 sq. ft. 5,000 sq. ft. 2,500 sq. ft N/A N/A”
  • Lot coverageDistrict specific (with conditions)

    Maximum lot coverage in the unincorporated Montalvin Manor P-1 development-standard districts shown in the County guideline table.

    • The table contains multiple land-use/zoning columns; the applicable maximum depends on the specific district/use column.
    • The source does not establish a single countywide lot-coverage limit.

    maximum lot coverage: 35%; 35%; ---; 50%; ---; 50%; 40% percent (varies by table column)

    “Maximum Lot Coverage 35% 35% --- 50% --- 50% 40%”
  • Building heightDistrict specific (with conditions)

    Maximum building height in the unincorporated Montalvin Manor P-1 development-standard districts shown in the County guideline table.

    • The table contains multiple land-use/zoning columns; the applicable maximum depends on the specific district/use column.
    • Where the area abuts a single-family residential district, the portion of the district within 50 feet of that district has a 20-foot maximum.
    • Detached accessory structures covered by the source note may be no higher than 15 feet.

    maximum building height: 50 ft.; 30 ft.; 50 ft.; 35 ft. or 2 1/2 stories; 20 ft.; 35 ft.; 35 ft. feet/stories (varies by table column) · abutting single-family district height limit: 20 feet (portion within 50 feet of the abutting single-family residential district)

    “Maximum Building Height 50 ft. 30 ft.(b) 50 ft. 35 ft. or 2 1/2 stories 20 ft. 35 ft. 35 ft.”
  • Living in an RVLimited

    Human habitation, including sleeping, in a recreational vehicle or travel trailer in unincorporated Contra Costa County.

    • The county rule applies to unincorporated areas; incorporated municipalities may have separate rules.
    • Human habitation, including sleeping, is prohibited except where the use is authorized by Articles 84-68.16, 84-68.18, or 84-68.20.
    • Occupancy is also excepted in a lawful mobile home park or travel trailer park.
    • Occupancy is also excepted in a lawful recreational vehicle park or campground allowed by a land use permit in A-2, A-3, RB, C, L-1, or T-1 districts.
    • Storage at a residence is not an occupancy authorization; the county states that storage of recreational vehicles on private property requires the vehicle not be used for living or sleeping and requires screening from public view.

    allowed RV park/campground zoning districts: A-2, A-3, RB, C, L-1, T-1 · storage screening requirement: >= 90 percent of mass screened from public view (Applies to storage, not authorization for human habitation)

    “No mobile home, recreational vehicle, or travel trailer shall be located, maintained or used for human habitation, including sleeping, in any land use district, except as follows:”
  • Tiny homesLimited

    Tiny-home occupancy in unincorporated Contra Costa County.

    • Contra Costa County has no planning regulation recognizing Tiny Homes.
    • Tiny homes on wheels are treated as recreational vehicles and may not be permanently used as mobile homes.
    • An accessory dwelling unit pathway requires a permanent foundation and a property with an existing primary residence.
    • Mobile homes must comply with County Code Section 84-68.20 for temporary use; permanent mobile homes on an undeveloped lot are directed to County Code Section 84-68.16.
    “Contra Costa County has no planning regulation recognizing “Tiny Homes”.”
  • Accessory dwellingsAllowed (with conditions)

    Accessory dwelling units in unincorporated Contra Costa County.

    • ADUs require both planning and building approvals.
    • Applicants must obtain Planning approval before submitting a Building Permit application.
    • Completed ADU planning and building checklists are required.
    • If the property has a septic system, plans must be reviewed by Environmental Health.
    • ADUs are not allowed to be permitted for short-term rental use.
    • Junior ADUs have a maximum size of 500 square feet and are only allowed in single-family residential districts.
    • A detached ADU up to 800 square feet and up to 16 feet in height has streamlined processing and is not subject to parking requirements.
    • The County provides building-permitting services for Clayton, Hercules, Lafayette, Orinda, and Moraga, but those cities require city planning approval before County building-permit submission.

    junior ADU maximum size: <= 500 square feet · streamlined detached ADU maximum size: <= 800 square feet · streamlined detached ADU maximum height: <= 16 feet

    “ADUs require both planning and building approvals. The process is the same if the applicant is legalizing an existing ADU or constructing a new ADU.”
    One more reviewed finding on this topic
    • Allowed (with conditions) — Accessory dwelling units in unincorporated Contra Costa County.
      “ADUs require both planning and building approvals.”
  • Who permits septicCounty

    Properties with septic systems and wells in Contra Costa County, including unincorporated properties subject to County permitting processes.

    • Sanitary or sanitation districts administer sewer-service approvals where applicable.
    • Incorporated municipalities may have their own planning and building-permitting services.
    “Serves properties with septic systems and wells. Projects with septic systems or wells require Environmental Health approved plans at application submittal.”
  • Septic permitRequired

    Construction, replacement, alteration, abandonment, vault privy, or sewage holding tank work for onsite wastewater treatment systems in Contra Costa County.

    • The application form identifies multiple OWTS permit categories, including conventional, alternative, alteration, replacement, abandonment, vault privy, and sewage holding tank work.
    • The application is not itself the permit.
    • Approved permit conditions and applicable laws and regulations must be followed.
    • Written authorization is required before deviating from approved plans or placing the system in service.
    “ONSITE WASTEWATER TREATMENT SYSTEM (OWTS) CONSTRUCTION PERMIT APPLICATION”
  • Septic inspectionRequired

    Permitted onsite wastewater treatment system work in Contra Costa County.

    • Inspections are required under the permit application certification.
    • The approved permit and plans must be maintained at the job site until final approval.
    • Written authorization is required before deviations from approved plans or placing the system in service.
    “I agree to obtain all required inspections, maintain a copy of the approved permit and plans at the job site until final approval, and obtain written authorization prior to deviating from the approved permit or plans, or placing the system in service.”
  • Off-grid sanitationLimited

    Off-grid sanitation forms specifically identified by the County Environmental Health OWTS application, including vault privies and sewage holding tanks.

    • The official OWTS application lists Vault Privy and Sewage Holding Tank as permit work types.
    • The application states that it is not itself the permit.
    • Approved permit conditions and applicable laws and regulations apply.
    • Required inspections must be obtained, and written authorization is required before deviations from approved plans or placing the system in service.
    “Vault Privy (53) Sewage Holding Tank (18)”
  • Well permitRequired

    Domestic, industrial, agricultural/irrigation, public/small water system, reconstruction, flow-test, and destruction work for water wells in Contra Costa County.

    • The official application requires one application per well.
    • A plot plan must be attached.
    • Required fields must be completed.
    • A variance is required for water-well annular seals less than 50 feet, as stated on the application.
    • The work must comply with permit conditions and applicable laws and regulations.
    • Required inspections must be obtained, and written authorization is required before deviations from approved permit conditions or placing the well in service.

    water-well annular-seal depth threshold for variance: < 50 feet (A variance is required when the annular seal is less than 50 feet.)

    “WATER WELL PERMIT APPLICATION APPLICATION FEE IS NON-REFUNDABLE (SERVICE FEES ARE ADDITIONAL REFER TO FEE SCHEDULE) ONE APPLICATION PER WELL”
  • Agricultural exemptionAvailable (with conditions)

    County business-license exemption for businesses engaged in growing livestock, poultry, or agricultural products for sale or disposal by the growers themselves.

    • The exemption is under the County Business License Ordinance and is not a blanket exemption from zoning, subdivision, building-permit, septic, or other land-use requirements.
    • The applicant must submit proof of exempt status with the application or renewal notice, such as state or federal certification or other documents if applicable.
    • Failure to submit proof may cause the County to deny or delay processing.
    “Businesses engaged in growing livestock, poultry or agricultural products for sale or disposal by the growers themselves. (Ordinance 91-35 Section 1).”
    One more reviewed finding on this topic
    • Available (with conditions) — Building-permit exemption for shade-cloth structures constructed for nursery or agricultural purposes in Contra Costa County.
      “Shade cloth structures constructed for nursery or agricultural purposes, not including service systems.”
  • Subdividing landRegulated (with conditions)

    Subdivision and related land-use entitlement applications for proposed development on properties in unincorporated Contra Costa County.

    • Applications are processed in conformance with local and relevant state regulations.
    • The California Environmental Quality Act (CEQA) applies where relevant.
    • The source describes review and processing of applications; it does not provide a complete subdivision-fee or map-approval schedule.
    “The Current Planning division is responsible for the review and processing of land use entitlements such as rezoning, subdivision, land use, development plan, tree permit, and variance applications in conformance with local, relevant state regulations, and the California Environmental Quality Act (CEQA) for proposed development on properties located within unincorporated Contra Costa County.”
    One more reviewed finding on this topic
    • Regulated (with conditions) — Subdivision applications for properties located within unincorporated Contra Costa County.
      “review and processing of land use entitlements such as rezoning, subdivision, [...] for proposed development on properties located within unincorporated Contra Costa County.”
  • Building in a floodplainRequired

    Construction of improvements within a FEMA-designated Special Flood Hazard Area in unincorporated Contra Costa County.

    • A Floodplain Permit is required for improvements within the SFHA.
    • An Elevation Certificate is required for new and substantial improvements.
    • The County states that the lowest floor, including basement, for all new structures or substantial improvements within an SFHA must be elevated one to two feet above the 100-year Base Flood Elevation.
    • The program is for unincorporated County areas only.
    • The written flood-zone determination fee is $100 per parcel; if a site visit is warranted, an additional $400 plus time and material fee applies.

    lowest-floor elevation above 100-year BFE: 1 to 2 feet · written flood-zone determination: 100 USD per parcel · site-visit surcharge: >= 400 USD plus time and material fee (applies if a site visit is warranted)

    “If you are constructing improvements within the SFHA, you are required to apply for a Floodplain Permit (PDF) from the Public Works Department”
  • Short-term rentalsLimited

    Short-term rentals in unincorporated Contra Costa County.

    • An STR may operate only after issuance of an STR permit; the permit is ministerial if all requirements are met.
    • Eligible property must be in unincorporated Contra Costa County and in a single-family, residential planned-unit, multifamily residential, or agricultural district not subject to a Williamson Act contract.
    • A land use permit is required to deviate from the standards.
    • Non-hosted STRs are limited to 90 rental days per calendar year; hosted STRs are limited to 180 days.
    • No more than one STR may operate on a lot.
    • A dwelling unit in a building containing five or more dwelling units may not operate as an STR.
    • Guest occupancy is limited to two persons per bedroom plus two additional persons, excluding children under 12.
    • Accessory dwelling units, events, excessive traffic/noise, road obstruction, and signage are prohibited; no more than 20 total persons may gather.
    • A business license and valid transient occupancy registration certificate are required before renting.
    • The permit expires one year after approval unless revoked sooner; renewal must be filed at least 30 calendar days before expiration.
    • Owners within 300 feet are noticed after permit issuance.

    non-hosted rental days: <= 90 days per calendar year · hosted rental days: <= 180 days per calendar year · notice radius: 300 feet · maximum STRs per lot: <= 1 STR · maximum occupancy: two persons per bedroom plus two additional persons persons (children under age 12 are not counted)

    “A non-hosted short-term rental may not be rented for more than 90 days in any calendar year.”
  • Permit feesVariable (with conditions)

    County-administered building and planning permits in unincorporated Contra Costa County.

    • Planning fees require a minimum application-based deposit and time-and-materials charges; the applicant is billed for any amount exceeding the deposit.
    • Building permit fees are based on project valuation.
    • Fees are outlined in the Land Development Fee Schedule.
    • The source states that new land development fees were adopted December 17, 2019 and implemented March 1, 2020.
    “Planning Fees require a minimum deposit based on the application. [...] Building Permit Fees are based on the valuation of the project.”
  • Permit processPublished (with conditions)

    Standard building permit applications administered by Contra Costa County in unincorporated areas.

    • The standard building permit submittal process is used for staff to determine required permits.
    • Larger projects require a plan check fee at the beginning of plan check; plan review begins after payment is confirmed.
    • Applications and plans must be submitted digitally through the ePermits Center; paper applications and plans are no longer accepted.
    “All Building Permit Applications are submitted through our ePermits System. The following resources can guide Applicants through the process.”

California rules that apply here

  • InspectionsRequired

    Construction projects within HCAI jurisdiction involving California health facilities.

    • HCAI field personnel make periodic site visits.
    • The Inspector of Record is responsible for continuous inspection of the work.
    • The inspections address seismic, fire, life-safety, and other building-code requirements.
    “The approved IOR with the required personal knowledge performs only those duties associated with the required continuous inspections”
    One more reviewed finding on this topic
    • Required — California owner-builder projects addressed by the Contractors State License Board guidance.
      “Your project must pass codes and building inspections.”
  • 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.”
  • SetbacksSpecified

    Qualifying SB 9 housing developments in single-family residential zones, including development of up to two primary residential units, subject to the cited statutory eligibility requirements and local ministerial review.

    • The parcel must be located in a single-family residential zone.
    • The project must involve no more than two residential units.
    • Objective standards may be applied only if they do not physically preclude the statutory housing objectives, subject to the stated exceptions.
    • No setback may be required for an existing structure or a structure constructed in the same location and to the same dimensions as an existing structure.
    • For SB 9 projects, side and rear setbacks may not exceed four feet; a local agency may apply a lesser setback, such as 0–4 feet.
    • The local agency cannot apply existing side and rear setbacks applicable in the single-family residential zones.
    • The four-foot side and rear setback standards are not subject to modification.
    • The fact sheet cites Government Code Sections 65852.21(b)(2)(B) and 66411.7(c)(3).

    maximum side setback: <= 4 feet (A local agency may choose to apply a lesser setback, including 0–4 feet.) · maximum rear setback: <= 4 feet (A local agency may choose to apply a lesser setback, including 0–4 feet.)

    “SB 9 establishes an across-the-board maximum four-foot side and rear setbacks.”
    One more reviewed finding on this topic
    • District specific (with conditions) — Building setbacks, side and rear yard requirements, and property line requirements under California's State Housing Law framework.
      “building setback, side and rear yard requirements, and property line requirements are hereby specifically and entirely reserved to the local jurisdictions”
  • 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.”
  • Manufactured homesAllowed (with conditions)

    Occupancy of manufactured homes inside or outside mobilehome parks in California.

    • The manufactured home must satisfy applicable federal standards and California Manufactured Housing Act and Title 25 requirements.
    • Installation and approval for occupancy are governed by the Mobilehome Parks Act.
    • HCD or a local enforcement agency with assumed Mobilehome Parks Act authority is responsible for ensuring compliance with statutory construction and maintenance requirements.
    • Local agency approvals may be necessary for the project.

    minimum width for a new manufactured home: >= 8 body feet (The statutory definition also includes units at least 40 body feet in length.) · minimum erected floor area for a new manufactured home: >= 320 square feet

    “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.”
  • Mandatory utility hookupSewer (with conditions)

    Certain existing OWTS in California Tier 3 impaired-water-body areas that commit to connect to a centralized wastewater collection and treatment system regulated through waste discharge requirements.

    • The OWTS must have been constructed and operating, or permitted, on or before the date the nearby water body was added to OWTS Policy Attachment 2.
    • The owner must commit by legally binding document to connect to a centralized wastewater collection and treatment system regulated through waste discharge requirements.
    • The owner must sign the legally binding document within 48 months after the nearby water body's initial listing on Attachment 2.
    • The specified connection date may not extend beyond nine years after the date the nearby water body is added to Attachment 2.
    • The rule is an exception to Section 10 requirements for qualifying existing or permitted systems; it is not a general statewide requirement that every property connect to public sewer.

    deadline to sign connection commitment: 48 months (Measured from the date the nearby water body is initially listed on Attachment 2.) · maximum time to complete connection: <= 9 years (Measured from the date the nearby water body is added to Attachment 2.)

    “The owner must sign the document within forty-eight months of the date that the nearby water body is initially listed on Attachment 2. The specified date for the connection to the centralized community wastewater collection and treatment system shall not extend beyond nine years following the date that the nearby water body is added to Attachment 2.”
  • Driveway accessRequired

    Driveways and driveway connections involving proposed encroachments within, under, or over State highway rights of way.

    • The requirement applies to proposed activities related to placement of encroachments within, under, or over State highway rights of way.
    • Applications are submitted to the appropriate District Encroachment Permits Office having jurisdictional authority over the site.
    • Local or other agency requirements may also apply outside State highway rights of way.
    “An encroachment permit must be obtained for all proposed activities related to the placement of encroachments within, under, or over the State highway rights of way.”
  • 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”

Inside cities and towns in Contra Costa County

Municipal rules found while researching the county. They apply inside that city or town, not to unincorporated land.

  • Local zoningPresent (with conditions)

    Properties within the City of Concord, Contra Costa County.

    • The Concord Planning Division provides zoning information and development standards.
    • The applicable rules depend on the property's zoning and the City's Development Code.
    “The Planning Division can assist you with information regarding zoning, permitted land uses, and development standards in the City of Concord.”
    One more reviewed finding on this topic
    • Present (with conditions) — Properties within the City of Richmond, Contra Costa County.
      “these regulations are adopted by the Richmond City Council to achieve the following objectives:”

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 Contra Costa 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 ↗
  • East Contra Costa Subbasin — Medium Prioritypartial of county

    Medium-priority SGMA basin (DWR 2019 Basin Prioritization) requiring an adopted Groundwater Sustainability Plan; a new well is subject to GSA consistency review under Executive Order N-7-22. De minimis domestic wells (<2 af/yr) are generally exempt from GSA metering but still need a county permit.

    California DWR — SGMA Basin Prioritization (2019) ↗

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 Contra Costa County, California

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

Contra Costa County scores 27/100 on the Bolthole Index, a weak county profile. Watch-outs: about 599,339 people within a 30-minute drive and elevated mid-century heat, water, rain, or wildfire exposure.

Do you need a building permit in Contra Costa County, California?

Contra Costa County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Contra Costa Health - Environmental Health Division (Land Use Program). 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 Contra Costa County?

Living in an RV on your own land in Contra Costa County is limited to specific cases: Human habitation, including sleeping, in a recreational vehicle or travel trailer in unincorporated Contra Costa County. The county rule applies to unincorporated areas; incorporated municipalities may have separate rules. Human habitation, including sleeping, is prohibited except where the use is authorized by Articles 84-68.16, 84-68.18, or 84-68.20. A tiny home is limited to specific cases. Confirm with the county before relying on it.

How much does land cost in Contra Costa County, California?

Land in Contra Costa County runs about $9,199 per acre, based on the latest county data.

What is the water situation in Contra Costa County?

Contra Costa County gets about 19.3" of rain a year, with severe drought in roughly 40.4% of years. On water rights, Contra Costa County lies in the East Contra Costa Subbasin — Medium Priority — Medium-priority SGMA basin (DWR 2019 Basin Prioritization) requiring an adopted Groundwater Sustainability Plan; a new well is subject to GSA consistency review under Executive Order N-7-22. De minimis domestic wells (<2 af/yr) are generally exempt from GSA metering but still need a county permit..

How remote is Contra Costa County?

A representative private-land location has about 599,339 people within a 30-minute drive and 12,666,427 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 Contra Costa County means bringing your own water and power. The kit we’d start with:

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How Contra Costa compares in California

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