AC and duct mold in Katy most often forms on the coil, in a drain pan that holds water, along attic ducts that sweat and around supply grilles. Removing it means fixing the moisture, cleaning or replacing the affected parts under a Texas protocol, and confirming clearance. Call the number on this page to be connected with a local mold remediation company in Katy.
Katy homes and their cooling systems
Katy grew from a railroad and rice-farming town about 19 miles west of Houston into the center of a large suburban area along I-10 and the Grand Parkway. Cane Island Creek, a branch of Buffalo Bayou, runs through the area. As in much of the Houston area, many homes are built on slabs with the air handler in the attic, so ducts and drain pans spend the summer in superheated air above cool living space. When a condensate line clogs or duct insulation slips, water has nowhere to go but into the pan, the insulation or the ceiling below. Heavy rain that raises indoor humidity adds to the load.
Steps to take right away
- Stop circulating the air. If you suspect mold inside the system, EPA says not to run it.
- Find the water. Check whether the condensate line drips outside and whether the pan is dry.
- Swap the filter. A soaked or moldy filter is a clue for the assessor; bag it and note what you saw.
- Keep humidity down. A portable dehumidifier can help hold rooms under 60 percent while you wait.
- Verify who's coming. Both the assessor and the remediation company should show on TDLR's license search.
Signs table
| What you see | Likely cause |
|---|---|
| Spots fanning out from a register | Humid room air meeting cold supply air |
| Musty odor on startup | Wet coil or a pan that won't drain |
| Brown ring on an upstairs ceiling | Overflowing attic pan |
| Water dripping from a vent | Sweating duct or boot with poor insulation |
| Mildew on the air handler cabinet | Leaky closet or attic air and high humidity |
Cost factors
National ranges (HomeGuide, 2026) put mold work on an HVAC system or ducts between $2,000 and $10,000, with Angi's Houston cost data reporting general mold removal typically $863 to $3,329. Attic access, the number of systems, how much flex duct is swapped and any drain or coil repairs set the total, plus the separate assessor's fee Texas law requires. Inside city limits, replacement work goes through the City of Katy Permit and Building Services Division (281-391-4830); Katy-addressed homes outside the city fall under Harris, Fort Bend or Waller County, depending on the address. City renters can report unrepaired building problems to the Code Enforcement Division.
AC & Air Duct Mold Removal questions in Katy
Are the dark specks around my AC vents mold?
Will fogging or spraying the ducts take care of it?
Why are two companies involved in one AC mold job?
What does AC and duct mold work cost near Katy?
More mold services in Katy
AC & Air Duct Mold Removal nearby
Sources
- EPA: Mold Cleanup in Your Home
- EPA: A Brief Guide to Mold, Moisture and Your Home
- TDLR: Mold Assessors and Remediators FAQs
- TDLR: License Search
- HomeGuide: How Much Does Mold Removal and Remediation Cost? (2026)
- Angi: How much do mold removal services typically cost? (Houston, TX)
- Wikipedia: Katy, Texas
- City of Katy: Permits and Building Services
- City of Katy: Code Enforcement
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