Water Damage Restoration & Mold Remediation in San Antonio, TX

San Antonio averages about 32 inches of rain a year, with May the wettest month and a second peak in September and October (NWS normals), but the averages hide the point: the city sits on the Balcones Escarpment (UT Bureau of Economic Geology) where thin soil over limestone sends rain straight into the creeks, and "flash floods can happen very quickly" (City of San Antonio). On June 12, 2025, 3 to 8 inches fell across the northern half of the city in a morning; 13 people died, 11 of them when vehicles were washed off a service road at Beitel Creek, and Leon Creek reached major flood stage (NWS Austin/San Antonio). October 1998 remains the record: 11.26 inches in a calendar day, 13.35 in 24 hours, 18.07 for the month, 31 deaths and three quarters of a billion dollars of damage across the region (NWS; NWS service assessment); May 25, 2013 is second with 9.87 inches in a day (NWS).

Under the eastern half of the city is the Blackland Prairie's Houston Black clay, which "extends from north of Dallas south to San Antonio" and whose very high shrink-swell potential is a recognized limitation for building (USDA NRCS, via TWDB); to the north and west, the Edwards Aquifer's karst limestone recharge zone covers about 1,250 square miles (Edwards Aquifer Authority). Slabs on the clay move and crack the pipes in them; houses on the limestone get water through the slab edge and the lowest wall. About 22% of San Antonio's housing predates 1960 (City of San Antonio Office of Historic Preservation), with the plumbing to match, and the 2021 freeze burst pipes in attics across the city.

San Antonio mornings average 83% relative humidity, 86 to 87% in summer (NCEI climate normals). The EPA's guidance is that wet materials dried within 24 to 48 hours usually won't grow mold (EPA); a creek flood through a ground floor, a slab leak under a kitchen, or a pipe patched after the freeze before the wall dried all run far past that.

Texas licenses mold work through the Department of Licensing and Regulation. Assessment and remediation are separate licenses, the same company can't do both on one project, and when a licensed remediation is finished you're owed a Certificate of Mold Damage Remediation within 10 days. Our mold remediation and mold inspection pages explain the rules and how to check a license.