The four steps
CDPH boils mold fixes down to four steps (CDPH):
- Find the damp or moldy areas.
- Fix the source of the moisture.
- Dry or replace wet materials.
- Clean or remove moldy materials.
A remediation plan that skips step 2 will likely be back.
What a professional job looks like
- Containment. CDPH says containment of the work area, including sealing HVAC vents, is an important safety measure, and larger projects may need plastic sheeting and negative pressure so spores don't spread.
- Protective gear. At a minimum, gloves, goggles and an N-95 respirator; CDPH notes that a dust mask won't protect you.
- Removal of porous materials. Drywall, ceiling tiles, insulation and carpet usually can't be effectively cleaned of mold. CDPH says porous materials that stayed wet more than a day or two may need removal even if they don't yet look moldy.
- Cleaning of hard surfaces. Scrub non-porous materials with soap or detergent and water. CDPH doesn't recommend bleach, and the EPA says to scrub hard surfaces with detergent and water and dry them completely (EPA).
- Drying to normal moisture levels before rebuilding.
- No shortcuts. CDPH says painting over mold, even after a biocide, won't fix the problem, and air cleaners alone won't solve it.
Who can do it?
CDPH says California has no licensing requirement for mold remediators; some hold IICRC, NORMI or NAMRI certifications. If the job includes construction, like replacing drywall or framing, the contractor needs a CSLB license for jobs of $1,000 or more (CSLB). Check licenses on CSLB. Our guide to choosing a mold remediation company has a full checklist.
Want a local pro to take a look?It's free for homeowners and there's no obligation.
DIY or pro?
The EPA says most homeowners can handle areas under about 10 square feet. Call a pro for larger areas, mold from sewage or floodwater, or suspected HVAC contamination, and don't run a system you suspect is contaminated (EPA).
Where we connect homeowners
- Mold removal in Santa Rosa
- Mold removal in Petaluma
- Mold removal in Rohnert Park & Cotati
- Mold removal in Windsor
- Mold removal in Healdsburg
- Mold removal in Sebastopol
- Mold removal in Sonoma
- Mold removal in Glen Ellen & Kenwood
- Mold removal in Cloverdale
- Mold removal in Guerneville & the lower Russian River
- Mold removal in Forestville
Other services
Dealing with this right now?Tell us what's happening and we'll connect you with an independent local provider.
Sources
- CDPH: Frequently asked questions about mold
- EPA: Mold cleanup in your home
- CSLB: disaster information
- CSLB: license check
Sources checked October 18, 2026.
Frequently asked questions
How long does mold remediation take?
Small jobs can take a day. Larger jobs with containment, demolition and drying often take several days, plus time for repairs.
Do I need to leave my home during remediation?
CDPH advises that unprotected people avoid exposure during remediation. For larger jobs, ask the provider whether you should stay elsewhere.