State plumbing guide · CA

Plumbing in California

California sets a statewide plumbing code, licenses plumbing contractors at the state level, and has some of the country's strictest water-efficiency rules. Water hardness and housing age vary widely between cities, and so do the common calls.

Call (833) 878-1592Plumbing help across California

Median home built: 1977
Built before 1980: 55%
Owner-occupied: 56%
Winter: Hard freezes are rare; General statewide rating
Plumbing code: UPC
City guides: 16

Housing figures: U.S. Census Bureau, ACS 2024 1-year (B25035, B25034).

California city plumbing guides

How to check a plumber's license in California

Plumbing contractors in California hold a C-36 license from the Contractors State License Board, which offers a public Check a License search. [1]

What to check on a license and an estimate

California's older housing stock

Statewide, the median home was built in 1977 and 55% of homes predate 1980. Homes like that were usually built with copper supply, early plastic (ABS or PVC) drains, some cast iron. The city guides below show how much that varies within the state.

Which plumbing code applies in California

The 2025 California Plumbing Code (Title 24, Part 5), based on the 2024 Uniform Plumbing Code, took effect January 1, 2026. Cities such as Los Angeles adopt it with local amendments. [2]

California law requires single-family homes built on or before January 1, 1994 to have water-conserving fixtures. That means toilets of 1.6 gallons per flush or less, showerheads of 2.5 gpm or less and faucets of 2.2 gpm or less, and permitted alterations trigger replacement of noncompliant fixtures. [3]

Seasonal problems to plan for in California

Dry season: Water restrictions and high irrigation use; leaks and irrigation backflow devices get more attention.
Winter storms: Heavy rain can overwhelm drains and sewer laterals in older neighborhoods, especially where roots have entered clay pipe.

Regions of California

Southern California

Imported Colorado River and Northern California water, hard water, and a large pre-1980 housing stock.

Bay Area

Hetch Hetchy water in San Francisco; blended groundwater and imported water in San Jose; very old housing in the city.

California plumbing questions

How do I check a plumbing contractor's license in California?

Use the Contractors State License Board's Check a License search, and look for the C-36 plumbing classification.

Do I have to replace old toilets when I remodel in California?

For single-family homes built on or before January 1, 1994, permitted additions and alterations require replacing noncompliant fixtures (for example, toilets over 1.6 gallons per flush) with water-conserving ones.

Town not listed?Plumbing problems Services Call (833) 878-1592

Sources (4)

U.S. Census Bureau, ACS 2024 1-year (B25035, B25034) · checked 2026-10-01
Contractors State License Board · checked 2026-10-01
IAPMO, 2025 California Plumbing Code errata (effective January 1, 2026) · checked 2026-10-01
California Civil Code §1101.1–1101.8 · checked 2026-10-01