A C20 license is a contractor classification that varies significantly by state, but generally covers specialty trades that don't fit into the main contractor categories.
The term "C20" itself comes from California's licensing system, where it designates a specialty contractor license. However, not every state uses this exact classification, and the work it covers differs depending on where you live. In California, a C20 license historically covered asbestos abatement and lead-based paint removal — highly regulated work that requires specific training and certification. Other states have adopted similar numbering systems but assign different trades to the C20 designation, or they may not use C20 at all.
If you're looking at contractor licensing in your state, the C20 label alone doesn't tell you what work is actually covered. You need to check your state's contractor board or licensing authority to see what that specific number means in your jurisdiction. Some states group specialty trades under different numbers entirely, while others don't use numbered classifications at all.
Key Takeaways
- C20 licensing is not uniform across states — the same number can mean different trades depending on where you live.
- In California, C20 historically referred to asbestos abatement and lead-based paint removal, both requiring specific certifications.
- Your state's contractor board website will show what work a C20 license actually covers in your area, if that classification exists at all.
- Specialty contractor licenses typically require proof of experience, passing an exam, and proof of workers' compensation insurance before you can get licensed.
- Some states have moved away from numbered classifications entirely, using descriptive license types instead.
How C20 Licensing Works in California
California's Contractors State License Board (CSLB) uses a lettered and numbered system to classify contractor types. The C20 classification was created to regulate contractors performing asbestos-related work — specifically abatement, removal, and encapsulation. Because asbestos exposure poses serious health risks, California requires anyone doing this work to hold a C20 license and to have completed the state's asbestos training and certification requirements.
To get a C20 license in California, you must pass the CSLB's written exam, which tests knowledge of asbestos regulations, safety protocols, and California law. You also need to show four years of experience in asbestos abatement work within the past ten years, or you can substitute certain certifications from the state's Department of Industrial Relations. Workers' compensation insurance is mandatory, and you must have a responsible managing officer or responsible managing employee on your team who holds the C20 classification themselves.
The license is not permanent — California requires renewal every two years, and you must complete continuing education hours related to asbestos safety and regulations. The CSLB also conducts inspections and investigations if complaints are filed, and violations can result in fines, license suspension, or revocation.
C20 Licensing in Other States
States that have adopted contractor licensing systems don't always use California's numbering scheme. Some states have their own systems entirely. For example, Texas uses a different classification structure through its Department of Licensing and Regulation, and Florida's Division of Regulation uses yet another system. If you're looking for specialty contractor licensing in your state, you need to contact your state's licensing board directly rather than assuming C20 means the same thing everywhere.
Some states regulate asbestos work through separate certifications rather than contractor licenses. New York, for instance, requires asbestos abatement contractors to be licensed through the Department of Environmental Conservation, not through a general contractor board. Massachusetts has its own asbestos contractor licensing program. The point is that the specific license type, the name, and the requirements all depend on your state's regulatory structure.
If you're researching contractor licensing for a specific trade in your state, start by searching "[your state] contractor license types" or "[your state] specialty contractor license" along with the trade name. Your state's licensing board will have a complete list of what classifications exist and what each one covers.
Experience and Exam Requirements for Specialty Contractor Licenses
Most states that issue specialty contractor licenses require documented work experience before you can sit for the exam. The amount of experience varies — California requires four years for C20, but other states may require two, three, or five years depending on the trade. You typically need to show this experience through employment records, tax returns, or letters from previous employers, and the work must fall within the specific category the license covers.
The written exam tests your knowledge of the trade itself, relevant safety regulations, and your state's contractor laws. Some states allow you to take the exam multiple times if you fail, while others limit attempts or require a waiting period between retakes. Exam fees vary by state and license type, typically ranging from $50 to $300. You can usually find study materials and sample exams on your state's licensing board website.
Insurance requirements are nearly universal for specialty contractor licenses. You must carry workers' compensation insurance (required in most states if you have employees) and often general liability insurance as well. Some states specify minimum coverage amounts. You'll need proof of insurance before the license is issued, and you must maintain it continuously — letting it lapse can result in license suspension.
When You Need a Specialty Contractor License
You need a contractor license when your state law requires one for the work you're doing. This is not optional — performing licensed work without a license is illegal and can result in fines, criminal charges, and civil liability if something goes wrong. The question is whether the specific work you're doing falls under a licensed category in your state.
For example, if you're doing asbestos abatement in California, you must have a C20 license. If you're doing the same work in a state that doesn't use that classification, you still need whatever license that state requires for asbestos work — you just need to find out what it's called. If you're doing general carpentry or plumbing, you may need a general contractor license or a trade-specific license depending on your state's rules.
The safest approach is to contact your state's contractor licensing board before you start any work and ask directly: "Do I need a license to do [specific work]?" They can tell you whether a license is required, what it's called, what it costs, and what the requirements are. Many states also allow you to look up licensed contractors in your area, which can help you understand what license types exist.
Checking Your State's Licensing Requirements
Your state's contractor licensing board is the only authoritative source for what licenses exist in your state and what they cover. Most states have a website where you can search for license types, read exam study guides, and find the process process. Some common places to look: your state's Department of Consumer Affairs, Department of Licensing, or a dedicated Contractors State License Board.
When you find your state's licensing board, look for a section on license types or classifications. This will show you what licenses are available and what work each one covers. If C20 is listed, the board will explain what it means in your state. If it's not listed, you'll see what the equivalent license is called instead. You can also call the board directly — most have phone lines staffed during business hours, and staff can answer basic questions about whether you need a license for specific work.
Keep in mind that licensing requirements can change. States sometimes add new license types, retire old ones, or shift the work covered by existing licenses. If you're planning to get licensed or hire a contractor, check the current requirements on your state's official board website rather than relying on information that might be a few years old.
Hiring a Licensed Contractor vs. Doing the Work Yourself
If you're hiring someone to do specialty work like asbestos abatement, you should verify that they hold the correct license for your state. Ask to see their license, and you can usually verify it online through your state's licensing board — most boards have a searchable database of active licenses. A valid license means the person has met your state's experience and exam requirements and carries the required insurance.
If you're considering doing the work yourself, understand that licensing requirements exist for safety and legal reasons. Asbestos work, for example, is regulated because improper removal can release fibers that cause serious lung disease. If your state requires a license and you do the work without one, you're breaking the law and potentially exposing yourself and others to harm. The same applies to any other licensed trade in your state.
Some states allow homeowners to do certain work on their own property without a license, but this exemption is usually limited to very specific situations and doesn't explore to all trades. Even if an exemption exists, you may still need to pull permits and have the work inspected. Check your local building department or contractor board to understand what you're allowed to do yourself.
Frequently Asked Questions
Is a C20 license the same in every state?
No. C20 is a California classification, and other states either use different numbers for the same work, use different names entirely, or don't use numbered classifications at all. You must check your specific state's licensing board to see what licenses exist and what they cover.
How much does a C20 license cost in California?
California's CSLB charges an exam fee and an process fee, which together typically total between $200 and $400, though fees can change. You'll also need to pay for workers' compensation insurance, which varies based on your payroll and claims history. Check the CSLB website for current fee amounts.
Can I work as a contractor without a license if I'm just starting out?
No. If your state requires a license for the work you're doing, you must have it before you start — there is no grace period for new contractors. Working without a required license is illegal and can result in fines and criminal charges.
How do I verify that a contractor I'm hiring actually has a valid license?
Most states have a searchable database on their contractor licensing board website where you can look up a contractor's name or license number. You can also ask the contractor directly for their license number and verify it yourself. A valid license should be current and match the type of work they're doing.
What happens if a contractor's license expires while they're working on my project?
The work should stop until the license is renewed. If a contractor continues working with an expired license, they're breaking the law, and you could face liability issues if something goes wrong. Always check that a contractor's license is current before hiring them and periodically during longer projects.