Top 10 Best Plumbers in Marin County, California (Updated 2026)

What a C-36 plumbing license covers

A plumbing contractor in California holds a C-36 license from the Contractors State License Board. CSLB describes the work as providing a supply of safe water and the proper disposal of fluid waste from a building.

The classification reaches further than sinks and drains. According to CSLB's license classifications, C-36 also covers gas piping and gas appliances with their flues, water and gas lines from the owner's side of the utility meter to the building, equipment that heats water (solar water heating included), and the connection of on-site waste disposal systems. Maintenance and replacement are in scope too, as are safety devices such as gas earthquake valves and backflow preventers.

One limit is written into the class. C-36 includes suspended gas space heating units but not forced warm air units. Warm-air heating systems belong to the C-20 license held by HVAC contractors.

When a plumber needs a license in California

CSLB's guide to what kind of contractor you need names three triggers. A current, valid license is required for anyone who contracts for work valued at $1,000 or more in combined labor and materials, who works on a project that requires a building permit, or who uses employee labor.

A remodel that mixes trades is handled differently. CSLB says that when a kitchen remodel involves plumbing, electrical and carpentry work under one contract, the right hire is a licensed "B" General Building contractor, who may do the work or subcontract parts of it to specialty licensees. The general contractors page covers that license, along with California's rules on home improvement contracts and payments.

Other license classes that touch plumbing work

Several other CSLB specialty classes sit close to plumbing. The class on the license tells you what the contractor may take on.

How to check a plumber's license

CSLB's lookup shows license status and complaint disclosure.

1. Ask for the contractor's license number. It has up to eight digits and no letters.
2. Enter it in CSLB's Check a License tool. You can also search by business name or by the name of a person on the license.
3. Confirm the license is current and carries the C-36 classification, or another class that fits the job.

CSLB also verifies licenses by phone at (800) 321-CSLB (2752). It accepts construction complaints against licensed and unlicensed contractors for up to four years from the date of the act. CSLB states that an investigation is not meant to obtain restitution, and that people whose main goal is money back should consider the courts.

Water heater strapping is California law

Health and Safety Code section 19211 requires all new and replacement water heaters, and all existing residential water heaters, to be braced, anchored or strapped so they resist falling or sliding in an earthquake. At a minimum the heater must be secured in line with the California Plumbing Code, or with a local amendment to it.

The seller of any real property that contains a water heater must certify to the buyer, in writing, that the heater complies. The certification can go inside existing sale documents, such as the sales contract or the transfer disclosure statement.

Building permits in Marin County come from the city or town where the property sits, or from the County of Marin for unincorporated areas. Those offices are listed on the government and services page.

Older Marin homes and water-saving fixtures

Civil Code sections 1101.1 to 1101.9 apply to residential and commercial property built and available for use on or before January 1, 1994, and they require owners to replace noncompliant plumbing fixtures with water-conserving ones. Census Bureau figures show that more than eight in ten housing units in Marin County were built before 1990 (American Community Survey, table B25034). The table does not show which of those homes already have newer fixtures.

The statute defines a noncompliant fixture by how much water it was made to use.

Under Civil Code section 1101.4, replacing these fixtures is a condition of final permit approval for alterations or improvements to a single-family home. A seller of a single-family home must also disclose in writing whether the property has any noncompliant fixtures.

One exception runs through the trade. The law does not apply to registered historical sites, or to property where a licensed plumber certifies that water-conserving fixtures are not technically feasible because of the age or layout of the building or its plumbing.

Plumbers are one of the trades listed in the home services section of this directory.

Who licenses plumbers in Marin County?

The California Contractors State License Board (CSLB) licenses plumbing contractors across the state, including Marin County. The license class is C-36 Plumbing. There is no separate county plumbing license. You can verify a license on the CSLB website or by calling (800) 321-CSLB (2752).

Does a plumber need a license in California?

Yes, in three situations. CSLB says anyone who contracts for work valued at $1,000 or more in combined labor and materials must hold a current, valid license. The same applies to any project that requires a building permit, and to anyone who uses employee labor, whatever the size of the job.

How do I check a plumber's license in California?

Use the Check a License tool on the CSLB website. You can search by license number, business name or the name of a person on the license. The record shows the license status and includes complaint disclosure. A California contractor license number has up to eight digits and no letters.

How do I file a complaint against a plumber in California?

File a construction complaint with the Contractors State License Board, online or with a printed form. CSLB takes complaints about licensed and unlicensed contractors for up to four years from the date of the act. CSLB notes that its investigations are not meant to obtain restitution, and points to the courts for that.

Does a water heater have to be strapped in California?

Yes. Health and Safety Code section 19211 says all new and replacement water heaters, and all existing residential water heaters, must be braced, anchored or strapped to resist falling or sliding in an earthquake. A seller of real property must certify in writing to the buyer that the water heater complies.

Do I have to replace old toilets and showerheads in California?

For property built and available for use on or before January 1, 1994, state law requires the owner to replace noncompliant plumbing fixtures with water-conserving ones. A toilet made to use more than 1.6 gallons per flush is noncompliant. So is a showerhead with a flow capacity above 2.5 gallons per minute.