Post-Flood Mold Removal in Houston, TX

Why Houston flood homes grow mold fast

Houston sits on flat, marshy ground on the Gulf coastal plain, and four major bayous carry the city's drainage, including Buffalo Bayou through Downtown and White Oak Bayou through the Houston Heights. Clay soils drain slowly, so water lingers around slab foundations after heavy rain. Add long, humid summers and a flooded house rarely dries on its own.

The flood history is long: Tropical Storm Allison dropped up to 40 inches of rain on parts of the city in 2001, and Hurricane Harvey damaged hundreds of thousands of homes in 2017. The Houston Health Department reported that Harvey put several feet of water into many areas that had never flooded and sat outside the mapped floodplain. Houston Public Works notes that flooding is possible outside FEMA's high-risk zones, so "we're not in a flood zone" is no reason to skip a mold check.

Order of work after the water goes down

1. Stop the water and get the house drying. Drying comes first, but it is not the same job as mold removal, and the mold work should not start on a structure that is still wet.
2. Photograph waterlines, damaged materials and belongings before anything is thrown out.
3. Keep children out of the cleanup. EPA advises that people with asthma or weakened immune systems stay away from moldy areas and that anyone handling wet materials wear at least an N-95 respirator.
4. Don't run central air if the air handler or ducts took water; EPA warns it can spread mold through the house.
5. Have a mold assessment consultant document the affected rooms and write the protocol.

What the remediation company removes and why

Soaked drywall, insulation, carpet and padding usually come out, because EPA says porous materials may have to be discarded once moldy. Crews typically cut wall board well above the waterline so the studs and bottom plates can be cleaned and dried. On pier-and-beam homes in older neighborhoods, the subfloor and the space underneath need attention too.

Texas rules that apply to flood jobs

• A homeowner may clean their own home. Anyone you hire for mold assessment or removal needs a TDLR license, and the consultant and the remediator must be different companies on the same project.
• For 25 contiguous square feet or more, the remediation company notifies TDLR at least five days before starting; flood jobs often pass that size.
• After clearance, you receive a Certificate of Mold Damage Remediation (CMDR). It can help with insurance underwriting, and you must give buyers any CMDR from the five years before a sale.

Cost and insurance

Angi's Houston cost data reports an average of $2,016 for mold removal, typically $863 to $3,329. Flood jobs often run larger: national ranges (HomeGuide, 2026) put 300 to 1,000 square feet at $6,000 to $15,000. Budget for the assessor as well. A standard homeowner policy does not include flood insurance, which is a separate NFIP policy.