When you start calling mold companies, you will hear a lot of letters: B, B-2, C-61, D-64. You may also hear that a company is "mold certified." This guide sorts out what California law actually requires, what it does not, and what to check before you sign.
Is there a mold license in California?
No. California does not issue a mold-specific license for remediation companies or inspectors. The Toxic Mold Protection Act only told the state health department to consider and report on the need for standards for mold testing professionals and mold remediation specialists. The Contractors State License Board (CSLB) list of license classifications has no mold class.
That does not mean mold work is unregulated. Removing drywall, replacing insulation and rebuilding are construction work, and California's Contractors License Law covers construction work above a set dollar amount.
When a CSLB license is required: the $1,000 rule
Under Business and Professions Code 7048, as amended by AB 2622 effective January 1, 2025, a contractor license is not required only for small jobs that meet all of these conditions:
- The total price for labor, materials and everything else is under $1,000. Before 2025 the limit was $500.
- The work does not require a building permit.
- The person does not employ anyone to do or help with the work.
Splitting a bigger job into smaller invoices to stay under the limit does not count. And an unlicensed person who advertises must say in the ad that they are not licensed, and can only advertise jobs under $1,000.
So in practice: any mold job of $1,000 or more, any job that needs a permit and any job done by a crew needs a CSLB-licensed contractor. Most real remediation jobs land well above $1,000. Published guides put a typical job at $1,500 to $9,000 (Fixr 2025), and even a 100 sq ft area runs about $1,000 to $2,500 (This Old House 2026).
| Example | CSLB license needed? |
|---|---|
| Handyman cleans a small patch of window-sill mold for $300, alone, no permit | Generally no |
| Same $300 job, but the handyman brings a helper | Yes, because someone else is employed |
| Containment and removal of mold in a bathroom wall, quoted at $2,400 | Yes, $1,000 or more |
| $800 drywall replacement that needs a building permit | Yes, because a permit is required |
| Crawl space cleanup and new vapor barrier, quoted at $1,800 | Yes, $1,000 or more |
Illustrations of B&P 7048 as amended by AB 2622. CSLB can answer questions about a specific job.
Which license class should a mold company have?
CSLB does not publish a mold-specific class, so no single class is "required for mold." The classification should fit the work being done. As examples only:
- B (General Building) or B-2 (Residential Remodeling) for tear-out and rebuild of walls, floors and ceilings.
- C-61 Limited Specialty with D-63 (Construction Clean-up) or D-64 (Non-specialized), which many restoration firms hold.
- C-2 (Insulation and Acoustical) for insulation work.
- C-20 (Warm-Air Heating, Ventilating and Air-Conditioning) for HVAC and duct work.
- C-22 (Asbestos Abatement) when asbestos-containing material is involved.
If you are unsure whether a class fits, ask the company to explain it, or call CSLB.
How to check a license
Ask for the number
A licensed contractor must put the license number on the contract. Ask for it at the first call.
Look it up
Use CSLB's free "Check A License" tool on cslb.ca.gov (CSLB also points to CheckTheLicenseFirst.com), or call CSLB at 800-321-CSLB (2752).
Match the details
Confirm the business name matches, the license is active and the classifications fit the work. Review the bond and workers' compensation information the record shows.
Contract rules that protect you
California's home improvement contract rules generally apply to residential jobs over $500, even though the licensing threshold is now $1,000. In general:
- Get it in writing. The contract should list the full price, the scope of work and the license number (B&P 7159).
- Down payment cap. A down payment may not exceed $1,000 or 10% of the contract price, whichever is less (B&P 7159.5). On a $4,000 job that is $400, not half up front.
- Progress payments generally may not get ahead of the work actually done.
- Three-day right to cancel for most contracts signed at home, or five days if you are 65 or older.
- Seven-day right to cancel for contracts to repair a home damaged by a disaster for which a state of emergency was declared by the President, the Governor or a local government.
After a fire, flood or storm: watch for door-knockers
Sonoma County has seen federal disaster declarations for the 2017 fires, the 2019 floods and the January 2023 storms. After events like these, unlicensed crews often go door to door.
California treats this seriously. Under B&P 7028.16, doing repair work without a license on damage from a disaster for which a state of emergency was proclaimed by the Governor or declared by the President is a crime, punishable by fines of up to $10,000 and possible jail or prison time. Check the license before anyone starts, and remember the seven-day cancel window on disaster repair contracts.
Permits, asbestos and lead
Mold cleaning and small tear-outs often need no permit, but rebuilding usually does. The City of Santa Rosa requires a building permit unless the California Building Code exempts the work. In unincorporated Sonoma County, Permit Sonoma exempts minor drywall repair only up to 100 sq ft. Ask the company or your building department. A permit requirement also means a licensed contractor is required at any price.
Half of Santa Rosa homes were built before 1980. In older homes, ask about an asbestos survey before drywall, flooring or ceiling texture comes out; asbestos work of 100 sq ft or more requires Cal/OSHA registration and a C-22 license. For homes built before 1978, ask whether the company is EPA Lead-Safe Certified.
Questions to ask every company
- What is your CSLB license number, and which classifications do you hold?
- Will you put the scope, price and payment schedule in a written contract?
- What is the down payment? (It should not exceed the lesser of $1,000 or 10%.)
- Who finds and fixes the water source?
- Does the price include post-remediation clearance testing, and who does it?
- Is the rebuild included, and who pulls the permit if one is needed?
Many homeowners prefer an inspector who does not also do the removal, so the person writing the scope is not the person selling the job. Our mold remediation process page walks through each step, and the mold removal page explains what companies typically do. For prices, see the cost guide.
Licensing and contract questions
Do I need a licensed contractor for mold remediation in California?
For most jobs, yes. California has no mold-specific license, but Business and Professions Code 7048 requires a CSLB-licensed contractor for any job of $1,000 or more in labor and materials, any job that needs a building permit, and any job where the worker employs someone. AB 2622 raised the limit from $500 to $1,000 starting January 1, 2025.
What license does a mold remediation company need in California?
There is no single required class. CSLB has no mold classification, so the license should fit the work. Examples include B or B-2 for tear-out and rebuild, C-61 with D-63 or D-64 for limited specialty work, C-20 for HVAC and C-22 for asbestos abatement. Check the company's license and classifications on CSLB's Check A License tool.
How much can a contractor ask for up front?
Generally no more than $1,000 or 10% of the contract price, whichever is less, under Business and Professions Code 7159.5. On a $3,000 mold job, that is $300. Progress payments generally should not get ahead of the work completed. A company asking for half the price before starting is a reason to pause and check the license.
Can I cancel a mold remediation contract in California?
Generally, contracts signed at home carry a three-day right to cancel, or five days for buyers 65 and older. Contracts to repair damage from a declared disaster, such as a wildfire or flood, generally carry a seven-day right to cancel. The contract should include the cancellation notice. This is general information, not legal advice.
Compare written quotes before you sign
Tell us what you see, where and whether there was a leak, and independent companies serving Santa Rosa, Petaluma, Rohnert Park and the rest of Sonoma County will reply with free quotes you can check on CSLB's lookup. Request a free quote or call (707) 896-6015. Santa Rosa Mold Pros is a free quote service: we pass your request to independent Santa Rosa, California area companies, and we do not inspect, remove mold or do construction work ourselves.