People often assume California has a detailed mold law: licensed mold inspectors, required tests, a legal spore limit. It does not. What it has is a 2001 mold act that was never fully put into effect, plus contractor, housing and contract laws that apply to mold work the same way they apply to other repairs.
General information, not legal advice. Santa Rosa Mold Pros is a free quote service, not a law firm or a contractor. Laws change, and your facts matter. For a specific dispute, talk to a California attorney or a local tenant or homeowner resource.
The quick answer
| Question | Short answer |
|---|---|
| Is there a California mold license? | No. California does not issue a mold-specific license. |
| Does a mold contractor need any license? | Yes, a CSLB contractor license for jobs of $1,000 or more, jobs needing a permit, or jobs using employees. |
| Does California set legal mold limits? | No. CDPH never adopted exposure limits for indoor mold. |
| Does California require mold testing? | No. The 2001 Act says testing is not required to decide if mold is a health threat. |
| Can mold make a rental substandard? | Yes, since 2016, when a health or code officer finds visible mold growth. |
| Do mold contracts have special protections? | The general home improvement rules apply: down-payment cap and cancel rights. |
The Toxic Mold Protection Act of 2001
The Toxic Mold Protection Act (SB 732, Health and Safety Code 26100 and following) asked the state health department, now the California Department of Public Health (CDPH), to do several things:
- Adopt permissible exposure limits for indoor mold.
- Develop standards for judging whether mold is a health threat, with an express rule that air or surface testing is not required to make that call.
- Write identification and remediation guidelines.
- Report on whether standards were needed for mold testers and remediators.
The Act also created disclosure duties for landlords and certain sellers. But those duties were written to start only after CDPH adopted the exposure standards and guidelines.
CDPH never adopted exposure limits. In a 2005 report it concluded that sound, science-based limits for indoor molds could not be established at that time, and later guidance pointed to visible mold, dampness and odor as better indicators. Because the standards were never adopted, the Act's disclosure duties that depend on them have not taken effect. There is no California number that makes a home pass or fail for mold.
No mold license, but contractor law still applies
California does not license "mold inspectors" or "mold remediators" as such. The Contractors State License Board (CSLB) has no mold classification. That does not make mold work unregulated. Generally:
- Any job of $1,000 or more in labor and materials must be done by a CSLB-licensed contractor (Business and Professions Code 7048; the threshold rose from $500 under AB 2622, effective January 1, 2025).
- Any job that needs a building permit requires a licensed contractor, whatever the price.
- Anyone who uses employees or helpers on the job needs a license, whatever the price.
- Splitting a job into smaller invoices to stay under $1,000 does not avoid the rule.
The license class should fit the work. Examples: B (General Building) or B-2 (Residential Remodeling) for tear-out and rebuild, C-61 limited specialty classes such as D-63 or D-64, C-20 for heating and air ducts, and C-22 for asbestos abatement. CSLB publishes no mold-specific class, so no single class is "the mold license." Check any license on CSLB's online license lookup. More on that in hiring a CSLB-licensed contractor for mold.
Rentals: when mold becomes a housing code problem
Since January 1, 2016 (SB 655), visible mold growth can make a rental substandard under Health and Safety Code 17920.3(a)(13) when a health officer or code enforcement officer determines it. Minor mold on surfaces that normally get wet, like a shower, is excluded. Civil Code 1941.1 also ties habitability to working waterproofing and plumbing.
Under Civil Code 1941.7, the landlord's duty to repair this kind of mold starts once the landlord has notice. Tenant remedies such as repair-and-deduct (Civil Code 1942) and rent protections when a unit has been cited (1942.4) come with strict conditions. Renters should notify the landlord in writing and keep copies. See California renters' mold rights and the rental and tenant mold page for both sides.
Selling a home with past or present mold
California sellers of most one-to-four-unit homes complete a standard disclosure process that asks about known conditions, and that process is generally understood to cover environmental hazards including mold. Disclose known water damage and repairs, and keep remediation invoices and clearance results. The Toxic Mold Act's own seller provisions are among those that depend on the standards CDPH never adopted. Details are in selling a house with mold in California; for your sale, ask your agent or an attorney.
Contract rules that protect you
Mold remediation contracts follow California's general home improvement rules. Generally:
- The contract should be in writing with the price, scope and the contractor's CSLB license number.
- The down payment cannot exceed $1,000 or 10% of the contract price, whichever is less (B&P 7159.5).
- You generally have 3 business days to cancel a home improvement contract, or 5 if you are 65 or older.
- Contracts to repair damage from a declared disaster, such as the Sonoma County fires and floods, generally carry a 7-day right to cancel (B&P 7159).
- Unlicensed contracting for repairs in a declared disaster area is a crime (B&P 7028.16). Be careful with door-to-door offers after a storm or fire.
Permits in Santa Rosa and Sonoma County
Cleaning mold and small tear-outs usually do not need a permit. Rebuilding often does. The City of Santa Rosa requires a building permit unless the California Building Code exempts the work. In unincorporated Sonoma County, including Guerneville, Forestville and Larkfield-Wikiup, Permit Sonoma exempts minor drywall repair only up to 100 square feet. Plumbing, electrical, HVAC, roofing and structural work generally need permits. Petaluma, Rohnert Park, Windsor and other cities run their own building departments. Ask the company or your building department.
Asbestos and lead in older homes
Half of Santa Rosa's homes predate 1980. Before tearing out drywall, flooring or duct wrap in a pre-1981 home, ask about an asbestos survey. Asbestos work of 100 square feet 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 before it disturbs painted surfaces.
What this means for you
Because California sets no mold limits and issues no mold license, your protection comes from choosing the right contractor and paper trail: a checked CSLB license where required, a written contract that respects the down-payment cap, a scope that fixes the moisture source, and a clearance check you understand. For the work itself, see mold removal and remediation and mold inspection and testing.
Frequently asked questions
Does California have a mold remediation license?
No. California does not issue a mold-specific license for inspectors or remediators, and CSLB has no mold classification. Contractor law still applies: any job of $1,000 or more, any job needing a permit, or any job using employees must be done by a CSLB-licensed contractor. Check the license number on CSLB's online lookup.
Does California set a legal limit for mold in homes?
No. The 2001 Toxic Mold Protection Act asked CDPH to adopt exposure limits, but CDPH found science-based limits for indoor mold could not be set and never adopted them. That is why the Act's disclosure duties tied to those standards have not taken effect, and why there is no state number a home must meet.
Does California law require mold testing?
No. California does not require homeowners to test for mold, and the 2001 Act specifically says air or surface testing is not required to decide whether mold is a health threat. Testing can still be useful for finding hidden mold or documenting clearance after remediation, but it is your choice.
Is mold a habitability issue for California renters?
It can be. Since 2016, visible mold growth can make a rental substandard when a health or code enforcement officer determines it, excluding minor mold on surfaces that normally get wet. The landlord's duty starts on notice. Remedies have strict conditions. This is general information, not legal advice; talk to an attorney or local tenant resource.
Need help with the work itself? Request free quotes from independent Santa Rosa, CA and Sonoma County companies, or call (707) 896-6015. Ask each one for its CSLB license number and a written scope.