Plumbing and HVAC rules in California

What the state says about plumbing and heating and cooling work, with the page each rule comes from. It's a summary of the published rules, not legal advice, and your city or county can have rules of its own.

Checked September 23, 2026

Plumbing licensing

A plumbing business in California holds a C-36 Plumbing Contractor license from the Contractors State License Board.^{1, 2, 3}

Heating and cooling licensing

A heating and cooling business in California holds a C-20 Warm-Air Heating, Ventilating and Air-Conditioning license from the Contractors State License Board.⁴

Plumbing and mechanical codes

Your local building department can tell you which plumbing and mechanical codes apply where you live.

Permits to replace a water heater, furnace or AC

Ask your local building department whether replacing a water heater, furnace or AC needs a permit where you live.

Backflow testing

If your home has a backflow preventer, your water utility can tell you whether it needs testing and who can test it.

Sources

What plumbing and HVAC work costs in California

Published national ranges for plumbing, water heater, sewer, AC, heat pump and furnace jobs, and a planning estimate for your own job.

Plumbing, heating and cooling costs in California

Contractors in California

28,029 plumbers and heating and cooling contractors are listed in California. 2,383 hold an active USDOT registration. Browse them by county, or ask for quotes and we'll pass your job to contractors near you.

Cite this page

“Plumbing and HVAC rules in California.” PlumbingInformationSite.com, updated September 27, 2026. https://plumbinginformationsite.com/ca/rules/