Mold Remediation & Removal Companies in California

If you have found mold in your home or business, you want it gone quickly, correctly, and for good. Below you will find a directory of independent mold remediation companies working across California, from the redwood coast and the Bay Area to the Central Valley, the deserts, and the Southern California basin. At Mold Inspection & Testing (MI&T), we provide independent mold inspection and testing only, we do not perform remediation, so the information on this page is offered as a free, unbiased resource to help you hire the right removal contractor with confidence.

Find a mold remediation company near you

Browse mold remediation companies serving your California city or county using the list below.

Before you hire anyone to remove mold, we strongly recommend starting with an independent mold inspection and test. Having an unbiased party confirm the type and extent of the problem, separate from the company that will do the removal, protects you from unnecessary work and gives you a clear scope to hold a contractor to.

MI&T is an inspection-and-testing company. We do not sell remediation, and we have no financial stake in which contractor you choose. We publish this directory as a courtesy so California property owners and renters can find qualified help and understand what good work looks like.

Why mold is a common problem in California homes

California's climate is remarkably diverse, and much of that diversity drives indoor moisture. Annual precipitation ranges from less than 3 inches in Death Valley in the southeast to more than 100 inches near Eureka on the northwest coast, according to the NOAA National Centers for Environmental Information State Climate Summary. Statewide totals swing wildly from year to year, from as little as 7.9 inches in 2013 to 42.5 inches in 1983, so the same house may face drought one winter and flooding the next.

Much of that moisture arrives in concentrated bursts. Atmospheric rivers, narrow bands of very moist tropical Pacific air, can dump extraordinary rainfall on the state; the 1996-1997 event delivered as much as 25 inches at some stations in under two weeks and caused more than $1 billion in damage. Along the coast, the marine layer keeps humidity high year-round, and inland flooding after these storms saturates walls, crawlspaces, and foundations. Wherever water intrudes and materials stay damp, mold can begin to grow within a day or two.

Wildfire adds a second, less obvious moisture pathway. Fires are a common late-summer occurrence, and the record-setting 2020 season included the largest single fire and largest fire complex in state history. Firefighting water, damaged roofs, and the heavy rains that follow burned-over ground all leave homes vulnerable to water damage and subsequent mold. In a state this large and varied, mold is less about one regional cause and more about the recurring pattern of water finding its way indoors.

Is mold remediation regulated in California?

California does not license or certify mold remediators or mold assessors. There is no state-issued "mold contractor" credential to look for. What is regulated is the underlying construction work: repairs, drywall replacement, plumbing, and similar tasks fall under the Contractors State License Board (CSLB), and a firm doing that work generally needs the appropriate contractor license.

On the health side, the California Department of Public Health (CDPH) has declined to set numerical or health-based permissible exposure limits for indoor mold, concluding that the available science did not support them. CDPH's guidance is straightforward: any indoor dampness, water intrusion, or mold growth should be identified and corrected promptly, regardless of the species. Because no license certifies competence specifically for mold work, the burden is on you to screen carefully. Look for voluntary industry certifications, current general liability insurance, written adherence to recognized standards, references, and a willingness to work from an independent inspection report rather than their own sales estimate.

Mold, renters, and landlords in California

California gives tenants meaningful protection when mold makes a home unhealthy. Every residential lease carries an implied warranty of habitability, established by the California Supreme Court in Green v. Superior Court (1974), which requires landlords to keep rental housing fit to live in. The Toxic Mold Protection Act of 2001 first directed the state to study mold, though it never produced enforceable exposure limits.

The most significant change came with SB 655 (2015). It amended the Health and Safety Code so that visible mold growth, as determined by a health officer or code enforcement officer to endanger the occupants' health, is a substandard housing condition under Health and Safety Code section 17920.3, and it connected that condition to Civil Code section 1941.1, which defines a landlord's duty to maintain habitable premises. The law specifically excludes minor mold found on surfaces that accumulate moisture as part of their properly functioning, intended use. In practice, this means a genuine mold problem can be treated as a habitability defect a landlord must address. Tenants facing an unresponsive landlord may have remedies such as repair-and-deduct or rent withholding tied to habitability. An independent inspection report can be valuable documentation if a dispute arises. This is general information, not legal advice; consult a qualified attorney or your local code enforcement office about your situation.

Standards a good remediator follows

Because California sets no technical standard of its own, the industry looks to national references. The strongest is the ANSI/IICRC S520 Standard for Professional Mold Remediation, which covers containment, worker protection, moisture control, and cleaning verification. Reputable contractors also follow U.S. EPA mold cleanup guidance and send any samples to accredited laboratories, such as those accredited under the AIHA Laboratory Accreditation Programs. A remediator who can explain how their scope maps to S520 and who welcomes independent verification is one worth shortlisting.

How to choose a mold remediation contractor in California

Start with an independent inspection

Have the problem assessed and tested by a party that does not profit from the removal. You can schedule an independent inspection with MI&T at https://moldinspectionandtest.com/california. A clear report defines the scope so every bid is comparable.

Verify licensing and insurance

Confirm any construction-related work is performed under an appropriate CSLB contractor license, and ask for proof of current general liability insurance and, where applicable, workers' compensation coverage.

Ask about standards and get it in writing

Request a written scope referencing IICRC S520 and EPA guidance, including containment, moisture-source correction, and post-remediation verification. Beware anyone who cannot explain how they will confirm the job is done.

Compare bids and check references

Get more than one estimate against the same independent scope, read recent reviews, and ask for references from comparable California projects.

The information on this page reflects our understanding of California law and public guidance as of August 2026 and is provided as a courtesy for general information only. It is not legal advice. Statutes and regulations change; verify current requirements with the relevant California agency or a qualified professional before acting.

References

• NOAA NCEI, California State Climate Summary
• California Legislature, SB 655 (2015) — Housing standards: mold (bill text)
• California Health & Safety Code section 17920.3 (substandard conditions)
• California Civil Code section 1941.1 (untenantable dwellings)
• California Department of Public Health — Mold in the Home
• California Contractors State License Board (CSLB)
• ANSI/IICRC S520 Standard for Professional Mold Remediation
• U.S. EPA — Mold cleanup and remediation guidance
• American Industrial Hygiene Association (AIHA) — Laboratory Accreditation