Bolthole Index

Contra Costa County, California

Building permits, zoning and septic rules in Brentwood, California

Brentwood, California requires city building permits for most construction, remodeling and repairs.1 Brentwood sets its own zoning; Contra Costa Health handles septic-system review and well permits in Contra Costa County.23 Start with the city Permit Center for a project inside Brentwood city limits.4

At a glance

Building permits
City building permits required for most construction, remodeling and repairs1
Zoning
City zoning applies inside Brentwood city limits2
Septic
Contra Costa Health reviews septic plans and construction35
Accessory dwellings
ADUs allowed subject to city zoning, building and utility conditions6
Lot size
R-1-E: 14,500 square feet for permitted uses; 10,000 for conditionally permitted uses7
Wells
Contra Costa Health issues well permits and inspects drilling3
Building fees
Fees set by city council resolution; building and plan-check fees depend on project value81

Who to call

Building permits

City of Brentwood Building Section

City building permits, plan review and inspections

(925) 516-5405

150 City Park Wy, Brentwood, CA 94513

Also useful

City of Brentwood Permit Center

Submission of city building and planning applications

925-516-5405

[email protected]

150 City Park Way Brentwood, CA 94513

Planning & zoning

City of Brentwood Planning Division

City zoning and property regulations

925-516-5405

150 City Park Way Brentwood, CA 94513

Septic permits

Contra Costa Health Environmental Health — Land Use Program

County septic plan review, construction permits, inspections and well permits

925-608-5500

2120 Diamond Boulevard, Suite 100, Concord, California

Contact details are copied from each office’s official page and were checked against it on October 11, 2026.

Off-grid gear

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

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Do you need a building permit in Brentwood, CA?

Brentwood requires building permits for most building construction, remodeling and repairs, and most electrical, mechanical and plumbing installations, repairs and replacements.1 Brentwood has adopted the 2025 California Building Standards Code.9 A project exempt from a building permit still must comply with building and planning requirements.1 Ask the Building Section to classify the proposed work before construction, and ask Planning to check the proposed use and building location.110

Who issues building permits in Brentwood, and how do you apply?

The Brentwood Permit Center accepts city building and planning applications; contact the counter at 925-516-5405 or [email protected].4 Applications can be submitted through the Electronic Submittal Portal, by appointment, during City Hall walk-in hours, through the Permit Center drop-off area or by delivery service.4 Building-permit issuance follows application approval and payment of building-permit and other applicable fees.1 Brentwood sets permit fees by city council resolution, while building and plan-check fees depend on project value; request an estimate for the actual scope of work.81

Does Brentwood have zoning, lot-size rules and setbacks?

Brentwood has city zoning, and its Planning Division provides information about property regulations.210 In Brentwood’s R-1-E district, minimum lot area is 14,500 square feet for permitted uses and 10,000 square feet for conditionally permitted uses, with a separate approved-subdivision exception.7 Brentwood’s R-1 subzones generally require 20-foot front and rear yards, with cul-de-sac, corner-lot and access exceptions; side-yard requirements vary by subzone.11 Main buildings in R-1 are limited to 30 feet and two stories.12 Ask Planning to identify the parcel’s district before using these dimensions in a design.10

How do septic permits and wells work inside Brentwood?

Contra Costa Health’s Land Use Program reviews building plans on properties with septic systems and handles septic design review, construction permits and well permits.3 The county program describes a septic sequence of site and soil evaluation, percolation testing, system design, a construction permit and monitoring for an alternative system.3 A permitted septic project inside Brentwood must receive the required inspections, retain approved plans at the job site and obtain written authorization before deviations or placing the system in service.5 For a private well, California requires a local permit before construction, modification or destruction; Contra Costa Health reviews well designs and inspects drilling.133

Can you live in an RV or tiny home on land in Brentwood?

We could not confirm Brentwood’s rules for residential RV occupancy, temporary camping or tiny-home occupancy; ask the city Planning Division about the proposed living arrangement before buying land for that purpose.10 Brentwood does allow qualifying accessory dwelling units on legal lots, subject to its ADU chapter, underlying zoning and applicable building, utility, fee and parking conditions.6 Brentwood ADU side and rear setbacks are generally 4 feet, with specified exceptions.6 Ask Planning to evaluate a small dwelling as a specific project rather than assuming the ADU rules establish permission to live in an RV.10

What are the steps to building a home in Brentwood?

  1. Ask Brentwood Planning to identify the parcel’s zoning and review the proposed use, setbacks and height.101
  2. If the parcel uses septic or a well, contact Contra Costa Health about building-plan review and the relevant septic or well applications.3
  3. Submit the city building-permit application and required plans, and pay plan-check fees; the application includes an owner-builder or licensed-contractor declaration.1
  4. Obtain application approval and pay the building-permit and other applicable fees before permit issuance.1
  5. Schedule city building inspections through the automated system at (925) 809-7930, and obtain separate required septic inspections where applicable.15

What should you check before buying land in Brentwood?

Confirm the city-limit boundary before choosing a building or planning counter: the county building-permit rules apply to unincorporated Contra Costa County, while Brentwood’s Permit Center accepts city applications.144 For land outside Brentwood, see the Contra Costa County guide.14 Inside Brentwood, ask Planning about floodplain review, driveway access, sewer-connection requirements and the intended dwelling type; we could not confirm the complete city requirements for those issues.10 On a septic parcel, ask Contra Costa Health about the site evaluation before committing to a house layout, because its program reviews construction plans on septic properties.3

Watch-outs

  • Brentwood building-permit exemptions do not waive building or planning requirements.1
  • Brentwood’s RV and tiny-home occupancy rules remain unconfirmed; ask the city Planning Division about the exact proposed use.10
  • Contra Costa Health’s septic and well review applies to homeowners as well as professional contractors.3

Sources

  1. City of Brentwood Building Section (brentwoodca.gov)
  2. City of Brentwood, CA Code of Ordinances (Brentwood), quoted and re-checked
  3. Contra Costa Health Environmental Health — Land Use Program (cchealth.org)
  4. City of Brentwood Permit Center (brentwoodca.gov)
  5. Onsite Wastewater Treatment System Construction Permit Application (Brentwood), quoted and re-checked
  6. Chapter 17.715 Accessory Dwelling Units and Junior Accessory Dwelling Units (Brentwood), quoted and re-checked
  7. Chapter 17.120 R-1-E Single-Family Residential Estate Zone (Brentwood), quoted and re-checked
  8. Chapter 15.04 California Building Standards Codes (Brentwood), quoted and re-checked
  9. Chapter 15.04 California Building Standards Codes (Brentwood), quoted and re-checked
  10. City of Brentwood Planning Division (brentwoodca.gov)
  11. ecode360.com (Brentwood), quoted and re-checked
  12. ecode360.com (Brentwood), quoted and re-checked
  13. Well Standards (California statewide rule), quoted and re-checked
  14. Contra Costa County Frequently Asked Questions (2026 county census)

Written October 11, 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.

Answers from the rulebook for Brentwood

Brentwood’s own rules

  • Building code adoptedAdopted

    Construction inside Brentwood city limits.

    • The city adopted the 2025 California Building Standards Code by reference.
    • Fees are established by city council resolution.
    “California Building Standards Code, 2025 Edition”
  • Local zoningPresent

    Land inside Brentwood city limits.

    “The purpose of the R-1 (single-family residential) zone is to provide areas for three-and-one-half dwelling units per gross acre and areas of different lot sizes through the use of the R-1-6, R-1-8, R-1-10 and R-1-12 subzones and the specific regulations for each subzone as specified in this chapter.”
  • Accessory dwellingsAllowed (with conditions)

    Accessory dwelling units inside Brentwood city limits.

    • ADUs must comply with Chapter 17.715, underlying zoning, and other applicable municipal-code provisions, subject to the chapter's exceptions.
    • Detached and attached ADUs have size, setback, height, building-code, utility, fee, and parking conditions.

    detached ADU height: <= 16 feet (Up to 18 feet, with specified transit-related exceptions; attached ADUs have a separate height rule.) · ADU side and rear setbacks: >= 4 feet (Certain existing multifamily situations have exceptions.)

    “ADUs that satisfy the requirements of this Chapter 17.715 are allowed on a legal lot”
  • Permit feesVariable (with conditions)

    Permits issued under Brentwood Municipal Code Chapter 15.04.

    • Fees are established by city council resolution and may vary by permit or work type.
    “The fees for permits issued under this chapter are those established by resolution of the city council.”

Rules another office applies inside Brentwood

Brentwood does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • Minimum lot sizeSpecified

    R-1-E zone inside Brentwood city limits.

    • Permitted-use and conditional-use minimums differ.
    • Approved subdivisions have a one-acre maximum lot size and one-half-acre average lot size under the cited exception.

    permitted-use minimum lot area: 14500 square feet · conditionally permitted-use minimum lot area: 10000 square feet

    “Minimum lot area for permitted uses: fourteen thousand five hundred square feet”
  • SetbacksSpecified

    R-1 subzones inside Brentwood city limits.

    • Front and rear yards are uniform in the cited section; side yards vary by subzone.
    • Cul-de-sac, no-rear-access, and corner-lot exceptions apply.

    front yard: 20 feet · rear yard: 20 feet · R-1-6 side yard minimum: 5 feet (Sum of both sides 15 feet) · R-1-8 side yard minimum: 7 feet (Sum of both sides 20 feet) · R-1-10 side yard minimum: 9 feet (Sum of both sides 25 feet) · R-1-12 side yard minimum: 12 feet (Sum of both sides 30 feet)

    “Minimum front yard: twenty feet; [...] Minimum side yards: for each subzone as follows except as provided for in H-2 and H-3:”
  • Building heightSpecified

    R-1-E zone inside Brentwood city limits.

    • Accessory buildings are limited to one story and 15 feet; barns for large livestock may reach 35 feet if approved through conditional-use procedures.

    maximum main-building height: <= 30 feet (No more than two stories) · maximum accessory-building height: <= 15 feet (One story; qualifying barns may be 35 feet)

    “Maximum Building Height. No main building shall exceed the height of two stories and thirty feet and accessory buildings shall not exceed one story and fifteen feet except that barns, utilized within those subdivisions designed for large livestock may be constructed to a height of thirty-five feet if approved in accordance with the conditional use permit procedures.”
    One more reviewed finding on this topic
    • Specified — R-1 subzones inside Brentwood city limits.
      “Maximum Building Height Limit. No main building shall exceed the height of two stories and thirty feet.”
  • Septic inspectionRequired

    Permitted onsite wastewater systems inside Brentwood city limits.

    • Inspection requirements attach to the approved permit and plans; written authorization is required before deviating from them 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”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Brentwood or Contra Costa County directly.

  • Building permit — Building work inside Brentwood city limits.
  • Owner-builder exemption — Owner-builders performing construction inside Brentwood city limits.
  • Inspections — Building work inside Brentwood city limits.
  • Certificate of occupancy — Occupancy of buildings inside Brentwood city limits.
  • Minimum dwelling size — Dwellings inside Brentwood city limits.
15 more unanswered
  • Lot coverage
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Septic permit
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Subdividing land
  • Driveway access
  • Building in a floodplain
  • Short-term rentals
  • Permit process

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.

Unanswered questions are usually a sign that Brentwood publishes no rule on the point, not that none exists. Contra Costa County’s page lists the county offices to call.

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