Septic and Sanitation System Contractor Insurance in California (C-42)

What the C-42 license covers

The CSLB’s definition

“A sanitation system contractor fabricates and installs cesspools, septic tanks, storm drains, and other sewage disposal and drain structures. This classification includes the laying of cast-iron, steel, concrete, vitreous and nonvitreous pipe and any other hardware associated with these systems.”

Trench collapse is the injury risk that defines this trade, along with equipment and confined spaces. On the liability side, a failed system or a broken line can release sewage onto a neighbor’s property or into groundwater, and most general liability policies exclude pollution. Contractors pollution liability closes that gap, and many public and commercial contracts require it. Digging into a buried utility line is the other common claim.

The C-42 coverage stack

General Liability — add contractors pollution liability, since GL usually excludes sewage releases
Workers’ Compensation — rated 6307 or 6308 depending on each worker’s hourly wage
Commercial Auto — dump trucks, equipment trailers and service trucks
Inland Marine — excavators, backhoes and trench shoring
CSLB license bond — the $25,000 bond every C-42 license needs
Excess & Umbrella — municipal and commercial drain work often requires more

C-42 requirements

What California requires of a C-42 licensee

Requirement	What applies to C-42 sanitation system contractors
Contractor’s license bond	A $25,000 bond is required to activate and keep the license. LLC licensees also need a $100,000 LLC employee/worker bond. How the bond works
Workers’ compensation	Required now if you have even one employee. With no employees you can file a CSLB exemption, but that option ends for every classification on January 1, 2028. Check your requirement
General liability	Required by the CSLB only for LLC licensees (at least $1 million). General contractors and owners require it anyway, usually with additional insured status.

Workers’ comp class codes and 2026 rates

Class code	Description	Advisory rate per $100 payroll
6307	Sewer construction, workers paid under $45.00/hr	$7.45
6308	Sewer construction, workers paid $45.00/hr or more	$4.12

Source: WCIRB California, approved September 1, 2026 advisory pure premium rates and classification descriptions. These are benchmark loss costs, not quotes: each carrier files its own rates, and your experience mod and credits adjust the final premium.

The WCIRB’s footnote to Sewer Construction includes installing septic tanks and cesspools, and building storm drains and catch basins. Pumping and cleaning septic tanks is a separate class, 9426 ($6.83), so a company that both installs and services systems needs its payroll records split by type of work.

$45/hr

the wage line that splits 6307 from 6308

Pollution

usually excluded from GL; sewage releases need their own coverage

WC by 2028

every C-42 needs a policy, employees or not

Common questions

C-42 coverage, answered

What is the workers’ comp class code for septic installation in California?

Septic tank and cesspool installation is rated under Sewer Construction: 6307 for workers paid under $45.00 an hour and 6308 at $45.00 or more. The WCIRB’s 2026 advisory rates are $7.45 and $4.12 per $100 of payroll. Septic pumping and cleaning is a separate code, 9426.

Does general liability cover a sewage spill from a septic job?

Usually not. Most general liability policies exclude pollution, and sewage counts. Contractors pollution liability covers cleanup and third-party damage from a release caused by your work.

Is general liability required for a C-42 license?

Only for LLC licensees, at least $1 million. Counties, developers and general contractors will ask for it, often with additional insured status.

Do septic contractors need workers’ comp with no employees?

A C-42 with no employees can file the CSLB exemption until January 1, 2028. After that every licensee needs a policy.

Septic and Sanitation System Contractor Insurance in California

The CSLB’s definition

The C-42 coverage stack

What California requires of a C-42 licensee

Workers’ comp class codes and 2026 rates

C-42 coverage, answered

Get a C-42 quote that fits the work