Mold testing in Katy is an assessor's sampling of indoor air or suspect surfaces, read against an outdoor sample and a hands-on moisture check. It pays off when the source is hidden and makes little sense when you can already see the growth. Call the number on this page to be connected with a local mold inspector in Katy.

Katy in brief
Katy sits about 19 miles from Houston on I-10, where Harris, Fort Bend and Waller counties meet. It began as a railroad and rice-farming town and is now the center of a large suburban area. Cane Island Creek, a branch of Buffalo Bayou, runs nearby, and the flat prairie drains slowly after heavy rain. Inside the house, though, the most common moisture sources are the AC system and plumbing.
What to do now
- Trace the smell. Note whether it is strongest near a bathroom, a closet on an outside wall, or the vents when the AC starts.
- Look for water first. Check the condensate line and pan, the water heater, and the ceiling below any attic equipment.
- Don't spread it. If you suspect the HVAC system holds mold, EPA advises not running it.
- Hold off on cleaning. Leave the area as it is until the assessor has seen it and taken any samples.
- Verify who is coming. Paid testing in Texas requires a TDLR mold assessment license; check it on TDLR's license search.

Signs and what usually causes them
| What you see | Likely cause |
|---|---|
| Dusty-looking dark specks on supply registers | Cold vents meeting humid room air |
| Musty AC closet | Standing water in a pan or a slow drain line |
| Water ring on an upstairs ceiling | Attic drain pan overflow or a roof leak |
| Warped base cabinet floor | Leak at a dishwasher or sink connection |
| Mildew along window frames | Condensation on glass during humid stretches |
Cost factors
Angi's Houston cost data reports inspection and testing averaging $453, with typical jobs between $355 and $563. Sample count, an HVAC sample, home size and lab turnaround set the final price. HomeGuide's 2026 national range for an inspection on an average-sized home is $300 to $650. Inside city limits, rebuilding work needs a permit from the City of Katy Permit and Building Services Division, 281-391-4830, and the Code Enforcement Division handles building maintenance complaints. Addresses outside city limits fall under Harris, Fort Bend or Waller County, depending on location; on the Fort Bend side, the county health department does not take mold complaints.
Mold Testing questions in Katy
Will homeowners insurance pay for mold testing?
Can the air conditioning system be tested for mold?
Are store-bought mold test kits worth using?
Who can I hire to test for mold in Texas?
More mold services in Katy
Mold Testing nearby
Helpful guides
Sources
- EPA: Mold Information Slideshow (testing and sampling)
- EPA: A Brief Guide to Mold, Moisture and Your Home
- TDLR: Mold Assessors and Remediators FAQs
- TDLR: License Search
- Angi: Compare Quotes from Mold Inspectors & Testing Services (Houston, TX)
- Angi: How Much Does a Mold Inspection Cost?
- HomeGuide: How Much Does Mold Removal and Remediation Cost? (2026)
- Fort Bend County Health & Human Services: Environmental Health service area
- City of Katy: Permits and Building Services
- City of Katy: Code Enforcement
- Wikipedia: Katy, Texas
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