Mold can grow in drain pans, on coils, and in ducts, especially ducts running through damp crawlspaces. The EPA advises not running a system you suspect is contaminated. Here's how that plays out in Petaluma, what to do right now, and how to reach an independent, licensed local provider. Call (628) 336-1777 any time, or use the form on this page.
HVAC and duct mold in Petaluma: what we see
In older Petaluma homes, ducts running through damp crawlspaces can collect moisture and mold.
Petaluma's older homes often have ducts in damp crawlspaces, while newer east-side homes may have ducts in attics. Cool, damp air and leaky ducts can lead to condensation.
The local picture
Heating systems in local homes. House age and type determine what heating systems and ducts are common. Petaluma has older and historic homes on the west side near downtown and later subdivisions east of Highway 101.
Neighborhoods include the historic west side, downtown, and the east-side neighborhoods off North McDowell Boulevard. Conditions vary from street to street, so a provider should look at your specific home rather than assume.
What to do right now
- Turn off the system if you suspect mold in it.
- Note where the musty smell is strongest and when it happens.
- Check the filter and drain pan, if accessible.
- Don't spray chemicals into the ducts.
- Call an HVAC professional or mold provider for an inspection.
Want a local pro to take a look?It's free for homeowners and there's no obligation.
Petaluma checklist
- Seal and insulate ducts in crawlspaces.
- Change filters on schedule.
- Keep condensate lines clear.
- Control crawlspace humidity.
Local resources for Petaluma
- Permits: City of Petaluma
- Emergency alerts: SoCoAlert, the County's free notifications
- Sandbags: Sonoma County sandbag locations, updated during weather events
- Contractor licenses: CSLB license check
How a provider handles it
An inspection finds where growth is and why. The fix may include cleaning components, replacing lined or damaged ducts, and correcting the moisture source. For the full picture, read our complete guide and the deep dive Mold testing: what California says. We also have a storm-season article: Mold in rental housing.
Before you hire anyone, check the license on the CSLB site. Here's how we vet providers.
Dealing with this right now?Tell us what's happening and we'll connect you with an independent local provider.
More for Petaluma
- Mold removal in Petaluma: our full local page
- HVAC and duct mold service
- Flood mold cleanup in Petaluma: the Petaluma River, creeks and crawlspaces: our in-depth local guide
- Crawlspace mold in Petaluma
- Attic mold in Petaluma
- Bathroom mold in Petaluma
- Mold after flooding in Petaluma
- Same problem nearby: HVAC mold in Rohnert Park & Cotati, HVAC mold in Sonoma, HVAC mold in Sebastopol
- HVAC and duct mold in every Sonoma County town
Sources
Sources checked October 18, 2026.
Frequently asked questions
Who should I call for duct mold?
An HVAC contractor or a mold remediation provider.
Where are ducts usually in Petaluma homes?
In older homes, often in the crawlspace; in newer ones, often in the attic.
Will duct cleaning fix mold?
Cleaning addresses existing growth; moisture control prevents it. See EPA guidance.
Who should I call?
An HVAC contractor (check their CSLB license) or a mold remediation provider, depending on the scope.