In California, workers' compensation isn't optional once you have employees. It is one of the first policies a new business needs and one of the most misunderstood. This guide covers who must carry it, what it pays, how premiums are calculated, the special rules for contractors, and the mistakes that lead to audit bills and penalties.
The law: one employee is enough
California Labor Code §3700 requires every employer to secure workers' compensation coverage, either by buying insurance from an insurer authorized in California or by obtaining a certificate of consent to self-insure (practical only for large organizations). There is no minimum headcount. If you have one employee, part-time or full-time, family member or not (with limited exceptions), you need coverage. The Division of Workers' Compensation (DWC) explains employer obligations here: DWC – Employer information.
Failing to carry coverage is serious. Operating without workers' comp is a crime in California, and the Labor Commissioner can issue stop orders and penalties. If an uninsured employer's worker is injured, the Uninsured Employers Benefits Trust Fund may pay benefits and then pursue the employer for reimbursement. See the DIR page on illegally uninsured employers.
Employee or independent contractor?
California uses the ABC test from Dynamex and AB 5 (Labor Code §2775 and following) to decide whether a worker is an employee. Under the test, a worker is presumed to be an employee unless the business shows all three:
- A: The worker is free from the business's control and direction in performing the work.
- B: The work is outside the usual course of the hiring entity's business.
- C: The worker is customarily engaged in an independently established trade, occupation or business.
There are statutory exemptions for some professions and business-to-business relationships, but if you're unsure, assume you may owe coverage and talk to an employment attorney. Uninsured "1099" workers often show up at the year-end premium audit, and the insurer may charge premium for them.
What workers' comp pays
Workers' comp is no-fault coverage. It pays for:
- Medical care for a work-related injury or illness.
- Temporary disability benefits while the worker can't work.
- Permanent disability benefits if the injury causes lasting impairment.
- Supplemental job displacement benefits (vouchers for retraining in certain cases).
- Death benefits to dependents.
In exchange, workers' comp is generally the employee's exclusive remedy against the employer for workplace injuries. Most policies also include Part Two: employer's liability coverage, which responds to certain lawsuits that fall outside the comp system.
How the premium is calculated
California workers' comp premium is driven by three main factors:
- Classification codes. The Workers' Compensation Insurance Rating Bureau of California (WCIRB) maintains the classification system. Each code represents a type of work, such as clerical office employees or carpentry. WCIRB also publishes advisory pure premium rates by class.
- Payroll. Premium is calculated per $100 of payroll in each classification. Estimated payroll sets your deposit premium; actual payroll at audit sets the final premium.
- Experience modification (X-Mod). Once a business meets WCIRB's eligibility threshold, its own claims history is compared to the average for its class. A mod below 1.00 lowers premium; above 1.00 raises it. You can look up your mod on WCIRB's free X-Mod lookup.
Insurers then apply their own rates, schedule credits or debits, and fees. That's why quotes for the same business can vary meaningfully, and why shopping through an independent broker makes sense.
The premium audit: avoiding surprises
At the end of the policy term the insurer audits your actual payroll. Common audit problems:
- Misclassified employees, such as an office manager who also works in the field.
- Uninsured subcontractors. If a sub doesn't have its own coverage, its workers may be treated as yours. Always collect a current certificate of insurance before work starts.
- Underestimated payroll at the start of the year, which creates a large bill later.
Keep payroll records split by class, and tell your broker during the year if your payroll grows significantly.
Special rules for contractors
The Contractors State License Board (CSLB) requires licensees with employees to file a certificate of workers' compensation insurance or an exemption. Certain classifications (C-8 Concrete, C-20 HVAC, C-22 Asbestos Abatement, C-39 Roofing and D-49 Tree Service) must carry workers' comp even with no employees. SB 216 extends the requirement to all license classifications, and SB 1455 delayed that universal mandate to January 1, 2028. Confirm current rules on the CSLB workers' compensation page. Our contractor workers' comp by trade page breaks down what different trades face, and our workplace injury rates by industry page draws on public federal data.
A suspended license for lapsed workers' comp can stop jobs and payments, so treat renewal dates seriously.
Posting and notice requirements
California employers must post the official Notice to Employees poster identifying the insurer and how to report an injury, and give new hires the DWC written notice pamphlet. When an injury is reported, the employer must provide a claim form (DWC-1) within one working day. The DWC has free downloads: DWC employer notices.
Controlling costs the right way
- Safety programs. California requires an Injury and Illness Prevention Program (IIPP) under Cal/OSHA. Cal/OSHA Consultation Services offers free, confidential help: Cal/OSHA Consultation.
- Return-to-work. Modified duty can shorten disability periods.
- Prompt reporting. Claims reported quickly tend to be better managed.
- Correct classification from day one.
- Pay-as-you-go billing from some insurers ties premium to actual payroll each pay period, reducing audit surprises.
Getting coverage when you're new or high-risk
New businesses with no loss history can still get coverage. If the voluntary market declines a business, California's State Compensation Insurance Fund (State Fund) is the insurer of last resort and also competes in the open market. A broker can compare State Fund with private insurers.
Workers' comp checklist for California employers
- Buy coverage before your first employee starts.
- Classify every employee correctly and review classes annually.
- Collect certificates from every subcontractor.
- Post the required notice and give new hires the written notice.
- Provide a DWC-1 form within one working day of a reported injury.
- Check your experience mod on WCIRB each year.
- Keep payroll records split by class code for audit.
- If you're a contractor, keep your CSLB workers' comp filing current.
Need a quote or a second look at your classifications? Contact Alishahi Insurance or call (877) 711-4545.
Frequently asked questions
Do I need workers' comp in California if I have only one employee?
Yes. Labor Code §3700 requires every California employer with one or more employees to carry workers' compensation insurance or be approved to self-insure.
Do sole proprietors need workers' comp in California?
A sole proprietor with no employees generally isn't required to cover themselves, except for certain CSLB license classes such as roofing, concrete, HVAC, asbestos abatement and tree service; all classes are scheduled to need coverage from January 1, 2028. Check CSLB for current requirements for your license class.
What is an experience mod in California?
The experience modification is a factor calculated by the WCIRB comparing your claims history with the average for businesses in your class. Below 1.00 reduces premium; above 1.00 increases it.
What happens if I don't carry workers' comp?
Operating without required coverage can lead to stop orders, penalties, criminal charges, and personal liability for an injured worker's benefits.
Why did I get a bill after my workers' comp audit?
Audit bills usually come from higher actual payroll than estimated, misclassified employees, or uninsured subcontractors whose payroll was added to your policy.
Alishahi Insurance · 439 N Canon Dr, Penthouse, Beverly Hills, CA 90210 · (877) 711-4545 · CA License #4348151. General information only, not legal advice.