Well Drilling Contractor Insurance in California (C-57)

What the C-57 license covers

The CSLB’s definition

“A well drilling contractor installs and repairs water wells and pumps by boring, drilling, excavating, casing, cementing and cleaning to provide a supply of uncontaminated water.”

Drilling claims come from the rig: injuries around rotating equipment, rollovers on uneven ground, and the rig itself being damaged or stolen. On the liability side, a well that contaminates groundwater or damages a neighbor’s property can be costly, and standard general liability may limit pollution coverage. California also requires a C-57 license for drilling water, monitoring and geothermal heat-exchange wells.

The C-57 coverage stack

General Liability — check pollution and underground limits for water and monitoring wells
Workers’ Compensation — rated 6204, with 3724 for pump-only work
Commercial Auto — rig carriers, water trucks and support trucks
Inland Marine — drill rigs, tooling and pump-hoist trucks
CSLB license bond — the $25,000 bond every C-57 license needs
Excess & Umbrella — for public and agricultural contracts

C-57 requirements

What California requires of a C-57 licensee

Requirement	What applies to C-57 well drillers
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
6204	Drilling N.O.C., including water wells, casing and pumps installed with the drilling	$8.01
3724	Pump installation or repair on its own (millwright work)	$4.24

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.

Drilling water wells is code 6204, and it includes casing and pumps installed as part of the drilling job. Pump work on its own, such as replacing or repairing a pump on an existing well, is rated as millwright work, 3724, at about half the rate. Keep pump-only service separate in your payroll.

Code 6204

water well drilling, including casing and pumps

The rig

usually the largest property exposure

WC by 2028

every C-57 needs a policy, employees or not

Common questions

C-57 coverage, answered

What is the workers’ comp class code for well drilling in California?

Water well drilling is code 6204, Drilling N.O.C., with a 2026 WCIRB advisory rate of $8.01 per $100 of payroll. Pump installation or repair done on its own is code 3724 ($4.24).

Is general liability required for a C-57 license?

Only for LLC licensees, which must carry at least $1 million. Sole proprietors and corporations aren’t required to by the CSLB, but most general contractors and public agencies will require it before you start.

How do I insure my drill rig?

Drill rigs are usually covered under an inland marine (contractors equipment) policy, scheduled at their value, while the truck that carries them is covered under commercial auto. Make sure the rig’s value is current, because drilling equipment costs a lot to replace.

Do well drillers need workers’ comp with no employees?

Not yet. A C-57 licensee with no employees can file the CSLB exemption until January 1, 2028, when the exemption ends for every classification. Any employee means you need a policy now.

Well Drilling Contractor Insurance in California

The CSLB’s definition

The C-57 coverage stack

What California requires of a C-57 licensee

Workers’ comp class codes and 2026 rates

C-57 coverage, answered

Get a C-57 quote that fits the work