Antioch, CA Building Safety: Plumbing Permits (2026)

Plumbing permits in Antioch are issued by the Community Development Department Building Division under AMC Title 8, which adopts the current California Plumbing Code (CPC, Title 24 Part 5). Permits are required for water heater replacements (including tankless conversions), any new or replaced water, gas, waste, or vent piping, sewer lateral repairs or replacements, backflow prevention assemblies, water softeners, and fixture additions or relocations. Simple like-for-like fixture replacement (faucets, toilets, angle stops) generally does not require a permit when no piping is altered. Water heater replacements must comply with CPC Chapter 5, including seismic strapping (two straps), a properly sized T&P relief discharge to exterior, 18-inch platform height in a garage (or FVIR-listed appliance), and sediment trap on gas line. Tankless installations typically require both a plumbing permit and electrical or gas permit for venting and combustion air. Sewer lateral work on the private side connects to the City of Antioch sanitary sewer main and, for properties served by Delta Diablo, may trigger compliance testing for infiltration. California Civil Code 1101.1-1101.9 requires that single-family residences have water-conserving fixtures (1.28 gpf toilets, 2.0 gpm showerheads, 1.5 gpm bath faucets) installed by 2017, and compliance is verified at time of sale or major remodel. Cross-connection control for irrigation, fire service, and boilers is enforced under CPC 603 and the state Waterworks Standards.