REGULATIONS UPC SEISMIC REQUIRED

California Plumbing Code & Permit Rules

California Plumbing Code (based on UPC) (2022)

Data sources: State plumbing boards, ICC, IAPMO, EPA Last verified: 2026-03-16

UPC
Plumbing Code
Required
Annual Backflow Test
No
Homeowner DIY
Yes
Water Heater Permit

Plumbing Code

California follows the California Plumbing Code (based on UPC) (2022 edition).

CPC = UPC with heavy California-specific amendments; most restrictive state

The UPC (Uniform Plumbing Code) is maintained by IAPMO (International Association of Plumbing and Mechanical Officials) and is primarily used in western states. It covers similar topics to the IPC with some differences in pipe sizing and fixture requirements.

Backflow Prevention Testing

Annual testing is required in California for testable backflow prevention assemblies (RPZ, DCVA, PVB).

  • Residential: Yes — required for homes with irrigation systems or other cross-connections
  • Who can test: SWRCB-certified tester (new cert required from July 1, 2025)
  • Enforcement: Local water utility; service shut-off for non-compliance
  • Note: Strict enforcement; all assemblies protecting public water supply

Water Heater Installation

A permit is required to replace or install a water heater in California.

  • Licensed plumber required: Yes
  • Homeowner can DIY: No — licensed plumber required
  • Seismic strapping: Required — water heaters must be secured with upper and lower straps
  • Note: Mandatory seismic straps (upper + lower); C-36 license required; inspections mandatory

Universal requirements (all states):

  • Temperature & Pressure Relief (TPR) valve must be installed
  • Discharge pipe from TPR must terminate safely
  • Gas water heaters: proper venting required
  • Minimum 18" clearance from floor for gas heaters in garages
  • Expansion tank often required when backflow preventer is installed on main supply

Homeowner DIY Plumbing Rights

California requires a licensed plumber for plumbing work. Homeowner DIY is generally not permitted.

Licensed contractor (C-36) required for all plumbing work

Water Conservation Requirements

California has state-level water conservation requirements that exceed federal minimums.

Most restrictive: max 1.8 GPF toilets, 1.8 GPM showerheads, 1.2 GPM faucets (CalGreen)

Lead Service Line Replacement

Under the revised EPA Lead and Copper Rule (2021), California is required to inventory lead service lines and develop replacement plans.

$4.8B allocated for lead service line replacement (Prop 1)

Important Disclaimer

This information is provided as a general overview. Plumbing codes and regulations can vary significantly between municipalities within California. Always check with your local building department before starting any plumbing work. Local codes override state minimums — your city or county may have stricter requirements.

Sources

  • State plumbing boards and licensing agencies
  • International Code Council (ICC) — IPC adoption map
  • International Association of Plumbing and Mechanical Officials (IAPMO) — UPC adoption
  • EPA Safe Drinking Water Act — Cross-Connection Control Program
  • State building departments
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