Contra Costa County enforces 2025 CBC, T24 Pt 2 based on 2024 IBC with 2 local amendments on top. The amendments are the part that gets sets corrected. The state edition is only the floor.
Current edition
2025 Title 24
Prior edition
2022 Title 24
Code authority
Contra Costa County Dept. of Conservation and Development: Building Inspection
Edition changeover: Projects with a complete application on or before 2025-12-31 may still be reviewed under the 2022 Title 24.
Adopted code and local amendments by discipline
Adopted code editions and local amendments by discipline
Discipline
Adopted code
Local amendment
Building
2025 CBC, T24 Pt 2 based on 2024 IBC
Contra Costa County Ord. No. 2025-19 (adopted 2025-11-04): Title 7 Div. 74; 2025 codes w/ Ch. 74-4 seismic/concrete amendments (CBSC filing 2025-19-Partial)
Residential
2025 CRC, T24 Pt 2.5 based on 2024 IRC
n/a
Existing buildings
2025 CEBC, T24 Pt 10 based on 2024 IEBC
n/a
Fire
2025 CFC, T24 Pt 9 based on 2024 IFC
n/a
Electrical
2025 CEC, T24 Pt 3 based on 2023 NEC
n/a
Mechanical
2025 CMC, T24 Pt 4 based on 2024 UMC
n/a
Plumbing
2025 CPC, T24 Pt 5 based on 2024 UPC
n/a
Energy
2025 Energy Code, T24 Pt 6
n/a
Green / sustainability
2025 CALGreen, T24 Pt 11
n/a
Accessibility
2025 CBC Ch 11A/11B, T24 Pt 2
n/a
Wildland-urban interface
2025 CA-WUIC, T24 Pt 7 based on 2024 IWUIC
n/a
Historical buildings
2025 CHBC, T24 Pt 8
n/a
Administrative
2025 CAC, T24 Pt 1
n/a
Zoning
No state-adopted code
Local zoning ordinance (city or county), subject to state preemptionLocal text supersedes the state code
Unincorporated communities Contra Costa County reviews
These communities have no city building department of their own. The county is the authority having jurisdiction, so this page's code stack is the one that applies.
Alamo · Diablo · Kensington · El Sobrante · Bay Point · Discovery Bay · Pacheco · Blackhawk · Saranap
What Contra Costa County actually amended
Quoted from the adopted ordinance. These are the provisions that differ from the state code, which is where most correction lists come from. Excerpts, not the whole ordinance. Follow the source link for the full text.
106.1.1
Information on Construction Documents. Construction documents shall include dimensions and shall be drawn to scale on
suitable material. Electronic media documents may be submitted when
approved in advance by the building official. Construction documents
shall be of sufficient clarity to indicate the location, nature, and extent of
the work proposed and to show in detail that it will conform to this code
and all relevant laws, ordinances, rules, and regulations. The first sheet of
each set of plans shall include contact information for the owner and the
person or persons who prepared the plans. […]
106.2.1
Construction documents. Construction documents shall include dimensions and shall be drawn to scale on suitable material. Electronic
ORDINANCE NO. 2025-19
13
media documents may be submitted when approved in advance by the
building official. Construction documents shall be of sufficient clarity to
indicate the location, nature, and extent of the work proposed and to show
in detail that it will conform to this code and all applicable laws,
ordinances, rules, and regulations. The first sheet of each set of plans shall
include contact information for the owner and for the person or persons
who prepared the plans. […]
107.2.1
Information on Construction Documents. Construction documents shall include dimensions and shall be drawn to scale on
suitable material. Electronic media documents may be submitted when
approved in advance by the building official. Construction documents
shall be of sufficient clarity to indicate the location, nature, and extent of
the work proposed and to show in detail that it will conform to this code
and all relevant laws, ordinances, rules, and regulations. The first sheet of
each set of plans shall include contact information for the owner and the
person or persons who prepared the plans. […]
1905.6.2 · Seismic design categories C, D, E, and F. Structures assigned to
Seismic Design Category C, D, E, or F shall not have elements of structural plain
concrete, except as follows:
1.
Reserved.
2.
Isolated footings of plain concrete supporting pedestals or columns
are permitted, provided the projection of the footing beyond the
face of the supported member does not exceed the footing
thickness.
3.
Reserved.
(h)
Section 1906 (Footings for light-frame construction) of CBC Chapter 19 (Concrete) is
deleted.
(i)
Section 1907.5 (Minimum Slab Provisions – General) is added to Section 1907 (Slabs-
On-Ground) of CBC Chapter 19 (Concrete), to read:
Section 1907.5 Minimum Slab Provisions – General. […]
R602.10.4.5
Limits on methods GB and PCP. Method GB is not permitted, but gypsum board is permitted to be installed on the opposite side of the studs from
other types of braced wall panel sheathing. The use of Method PCP is limited to
one-story dwellings and accessory structures.
(e)
Appendix BB, Appendix BF, Appendix BJ, and Appendix CI of the CRC are
incorporated into the County building code. (Ords. 2025-19 § 3, 2022-35 § 3, 2019-31 §
3, 2016-22 § 3, 2013- 24 § 3, 2011-03 § 3.)
74-4.006 Amendments to CGBSC. The 2025 California Green Building Standards Code
("CGBSC") is amended by the changes, additions, and deletions set forth in this chapter and
Division 72. […]
SECTION II. · Section 74-2.002 (Adoption) of Division 74 (Building Code) of the County
Ordinance Code is amended to read:
74-2.002 Adoption.
(a)
The building code of this county is the 2025 California Building Code (California Code
of Regulations, Title 24, Part 2, Volumes 1 and 2), the 2025 California Residential Code
(California Code of Regulations, Title 24, Part 2.5), the 2025 California Energy Code
(California Code of Regulations, Title 24, Part 6), the 2025 California Historical Building
Code (California Code of Regulations, Title 24, Part 8), the 2025 California Existing
Building Code (California Code of Regulations, Title 24, Part 10), and the 2025
California Green Building Standards Code (California Code of Regulations, Title 24, Part
11), as amended by the changes,… […]
SECTION VII. · Section 72-6.212 of the County Ordinance Code is amended to read:
72-6.212 Expiration of permit.
(a)
A permit issued by the county building official becomes void if either of the following
occur:
(1)
The work authorized by the permit is not commenced within 12 months after the
permit issuance date. Evidence that work has commenced consists of at least one
approved inspection.
(2)
The work authorized by the permit is suspended or abandoned for a period of 12
consecutive months after the work is commenced. Work is deemed suspended or
abandoned for a period of 12 consecutive months if no approved inspection
occurs during that time.
(b)
A permittee holding an unexpired permit may apply to the county building official for a
permit extension. […]
SECTION III. · Chapter 74-4 (Modifications) of Division 74 (Building Code) of the County
Ordinance Code is amended to read:
Chapter 74-4
MODIFICATIONS
74-4.002 Amendments to CBC. The 2025 California Building Code (“CBC”) is amended by
the changes, additions, and deletions set forth in this chapter and Division 72. Section numbers
used in this section are those of the 2025 California Building Code.
(a)
CBC Chapter 1 (Administration) is amended by the provisions of Division 72 of this code
and as follows:
(1)
Sections 103 and 113 of CBC Chapter 1 are deleted.
(2)
In Section 105.2 (Work exempt from permit) of CBC Chapter 1 (Administration),
subsection 4, is amended to read:
4. […]
SECTION IV. · Section 76-2.002 (Adoption) of Division 76 (Electrical Code) of the County
Ordinance Code is amended to read:
76-2.002 Adoption.
(a)
The electrical code of this county is the 2025 California Electrical Code (California Code
of Regulations, Title 24, Part 3) (“CEC”), as amended by the changes, additions, and
deletions set forth in this division and Division 72.
(b)
The 2025 California Electrical Code, with the changes, additions, and deletions set forth
in Chapter 76-4 and Division 72, is adopted by this reference as though fully set forth in
this division.
(c)
At least one copy of this electrical code is now on file with the building inspection
division, and the other requirements of Government Code section 50022.6 have been and
shall be complied with. […]
SECTION VI. · Section 710-2.002 (Adoption) of Division 710 (Mechanical Code) of the County
Ordinance Code is amended to read:
710-2.002 Adoption.
(a)
The mechanical code of this county is the 2025 California Mechanical Code (California
Code of Regulations, Title 24, Part 4), as amended by the changes, additions, and
deletions set forth in Division 72.
(b)
The 2025 California Mechanical Code, with the changes, additions, and deletions set
forth in Division 72, is adopted by this reference as though fully set forth in this division.
(c)
At least one copy of this mechanical code is now on file with the building inspection
division, and the other requirements of Government Code section 50022.6 have been and
shall be complied with. […]
Mapped hazard and district overlays stack on top of the adopted code. These are the overlays recorded for Contra Costa County. They apply by parcel, not jurisdiction-wide, so confirm the parcel before assuming one is in play. Check CAL FIRE's fire hazard severity viewer and FEMA's flood map service.
Very High Fire Hazard Severity Zone
FEMA mapped flood hazard area
State law that overrides local zoning here
When one of these applies, the state statute governs over a conflicting local standard. This is the most common reason a local rule someone quotes you turns out not to be enforceable against a project.
Gov. Code 66310 et seq.
State ADU law preempts local zoning that would preclude a conforming ADU/JADU.
Applies when: project includes an ADU or JADU
Gov. Code 65915
State Density Bonus Law concessions/waivers override local development standards.
Applies when: project requests a density bonus
Gov. Code 65852.21 / 66411.7
SB 9 urban lot split / two-unit ministerial approval preempts conflicting local standards.
Applies when: project is an SB 9 lot split or two-unit development
Contra Costa County enforces 2025 CBC, T24 Pt 2 based on 2024 IBC, the edition adopted statewide in California, amended locally in 2 disciplines.
Does Contra Costa County amend the California code?
Yes: building, zoning.
Where do I confirm the code edition for a Contra Costa County permit?
With the county building department that will review the permit. Adoption ordinances are amended on a local schedule, and a set submitted days apart can fall under different editions during a changeover.
Knowing the adopted edition is the easy half. Architechtura reads your drawings, resolves which of these provisions actually apply to the project, and returns the corrections a plan checker would write up, each one cited to the section it came from.
Compiled from published state and municipal adoption ordinances. Local governments amend their codes on their own schedule, and a pending ordinance can change what applies to your permit. Confirm the governing edition with the building department before you submit. This page is reference information, not a code determination.