C-36 Plumbing Contractor license in California

Updated November 1, 2026 · Official name from CSLB's classification list

18,279licenses hold C-36
96%Clear (CA addresses)
51.2%workers' comp exempt (all: 49.6%)
100%contractor's bond on file
13.4 yrsmedian time licensed
54.3%businesses, not sole owners

C-36 plumbers deliver safe water to a building and carry waste away. CSLB's description covers water and gas piping from the owner's side of the meter, drains and vents, water heaters (solar included), gas appliances and flues, and on-site waste disposal. It also covers medical, compressed-air and vacuum piping, and safety devices like earthquake gas valves and backflow preventers.

Gas lines are plumbing, not HVAC, but forced warm-air furnaces belong to C-20. Old D-23 Medical Gas Systems work also sits here. C-36 is one of the classes that can add the HAZ certification.

Typical work under C-36

Water heater replacement, tank or tankless
Repiping a house
Gas lines to ranges, dryers and fire pits
Sewer line repair from the house to the street
Earthquake gas shutoff valves
Backflow preventers and pressure regulators

Work that needs a different license

Forced-air furnace installation: C-20 HVAC
Furnace ductwork: C-20 HVAC or C-43 Sheet Metal
Drilling a well for the house: C-57 Well Drilling

Tips before hiring

For a water heater, ask whether the price includes seismic straps, venting and permit fees.
For sewer work, ask for a camera inspection video before and after.
If the plumber adds a gas line, ask that it be pressure-tested and inspected.
Look up the license even for a small job. A plumbing job that needs a permit is outside the $1,000 minor-work exemption.

Where C-36 contractors are

The cities with the most C-36 license holders in CSLB's current file:

All plumbers lists

Cities with at least 20 C-36 license holders, largest first:

How to verify a C-36 license

Search the business or license number here and confirm C-36 is listed on the profile.
Check the same number on CSLB's Instant License Check.
Read our full guide to checking a contractor license.

Related license types

Source: CSLB public data · Updated November 1, 2026 Status can change at any time. Verify on CSLB's Instant License Check.

More license types: ← C-35 Lathing and Plastering Contractor · C-38 Refrigeration Contractor →