Because Antioch is located within Contra Costa County, the following broader county regulations may also apply to your project:
California, Contra Costa County Plumbing Permit Regulations and County Ordinances for Unincorporated Areas
Contra Costa County Plumbing Permit Requirements
Contra Costa County's Department of Conservation and Development (DCD) handles building permits, including those for plumbing, for properties located in unincorporated areas of the county. If your property is within an incorporated city, you must contact that city's building department directly, as the county does not issue permits for those locations.
Generally, major plumbing work, such as the installation of new systems or the rerouting of existing ones, requires a plumbing permit. Even if the overall building work does not require a permit, any associated electrical, plumbing, or mechanical work will still necessitate a trade permit.
Rules for Properties in Unincorporated Areas
For properties in unincorporated areas of Contra Costa County, a building permit is required for most construction and demolition projects. This includes, but is not limited to, the replacement of existing piping systems and the installation or replacement of water heaters, furnaces, and air conditioners.
Additionally, certain plumbing fixture replacements may trigger permit requirements, especially in conjunction with additions or alterations. California's SB 407 mandates that non-compliant plumbing fixtures be replaced with water-conserving fixtures when properties undergo additions or improvements. This applies to properties built on or before January 1, 1994, for single-family residences, and by January 1, 2019, for multifamily and commercial buildings.
Permits are also required if you bring utilities such as electricity or water to a structure, or enclose mechanical equipment like a well or pool pump.
The county utilizes an online ePermits Center for application submittal and management.
Resources to Learn More
The following statewide building codes and regulations apply universally to all jurisdictions within California:
California Plumbing Legislation, Codes, and Guidelines
California Plumbing Code and Legislation
In California, plumbing standards are governed by the California Plumbing Code (CPC), which is Part 5 of Title 24 of the California Code of Regulations. Unlike many other states that adopt the International Plumbing Code (IPC), California bases its plumbing code on the Uniform Plumbing Code (UPC). The state integrates the UPC with specific California amendments to address unique regional requirements, such as seismic safety, water conservation, and drought management.
The California Building Standards Code is updated on a triennial cycle. As of April 2026, the 2025 California Plumbing Code is the current enforceable standard, having taken effect on January 1, 2026. These regulations apply to all new construction, major renovations, and plumbing system installations across residential, commercial, and industrial properties throughout the state.
Primary State Agencies
The regulatory framework for plumbing in California involves several key entities:
- California Building Standards Commission (CBSC): The primary agency responsible for the formal rulemaking process, adoption, and publication of the California Building Standards Code (Title 24).
- Department of Housing and Community Development (HCD): Holds authority over building standards specifically related to residential housing.
- Contractors State License Board (CSLB): The agency responsible for licensing plumbing contractors (e.g., C-36 classification) to ensure that work is performed by qualified professionals.
- Local Building Departments: While the state sets the minimum standards, local city and county jurisdictions are responsible for enforcement, permitting, and inspection. These local authorities may also adopt stricter local amendments to the state code.
Resources to Learn More