California Workers Compensation High Rates by Class Code

Why California Class Codes Drive Workers Comp Costs

California workers compensation premiums are calculated by multiplying a rate per $100 of payroll by the employer's experience modification and payroll volume. That rate is attached to a class code, and some California codes carry rates far above the national average. Because the state uses a unique rating bureau formula and permits separate charges for medical treatment, the gap between low-risk and high-risk codes is wider here than in many other states.

What Makes a Class Code High-Rate in California

A class code is rated by the expected frequency and severity of claims for that occupation. In California, codes involving roofing, steel erection, heavy construction, logging, and certain manufacturing processes routinely appear among the highest. The Workers' Compensation Insurance Rating Bureau (WCIRB) sets the base rates, which then reflect California's elevated medical costs, disability duration trends, and litigation environment. When an employer has multiple operations under different codes, the high-rate codes can dominate the premium picture.

Examples of High-Rate Class Codes

While exact rates change annually, the following categories typically carry some of the highest premiums in California:

• Roofing – steep fall exposure and frequent claims
• Steel Erection – structural work at height
• Heavy Construction – excavation, concrete, and framing
• Logging and Timber – machinery and terrain hazards
• Hazardous Materials Manufacturing – chemical exposure risk
• Industrial Cleaning – chemical and slip hazards

A roofer in California may pay many times more per $100 of payroll than an office-based employer under class code 8810. The spread depends on the WCIRB rate schedule, the employer's experience modification factor, and any supplemental charges.

How California's Formula Amplifies the Differences

California calculates premiums on an experience-rating basis, meaning past claim history for each class code directly affects future costs. The state also allows medical-only claims to be rated differently, and it applies a separate administrative fee assessment. These layers mean that even a modest number of claims in a high-rate class code can push annual premiums well above budgeted amounts.

What Employers Can Do

Reviewing your classification with your auditor is the first step. Misclassified employees can inflate premiums, and correcting the code can lower costs immediately. For genuinely high-risk operations, implementing a strong safety program, return-to-work policy, and injury prevention plan can reduce claim frequency over time. Some employers also explore competitive bidding among carriers, since rate variations between insurers can be significant for the same California class code.