Flash floods in the Texas Hill Country don’t give much warning. Rain falls fast on thin, rocky ground, and a creek that was dry at dinner can be over the road by midnight.
San Antonio sits near the southern end of Flash Flood Alley, the stretch of Central Texas most prone to sudden flooding. The July 2025 floods along the Guadalupe River in Kerr County showed how fast it can happen.
Once the water stops rising, the next 24 hours decide how much of your home you save. Here’s how to use them.
Hours 1 to 2: make the house safe to enter
Don’t go back in until local officials say your area is safe. Check the outside first for a shifted foundation, a sagging roofline, or the smell of gas.
Standing water and live wiring are the biggest danger inside. If you’d have to step into water to reach the breaker box, don’t. Call an electrician or your utility to cut power at the meter.
Treat all floodwater as contaminated. It can carry sewage, fuel, and chemicals, so wear rubber boots and gloves, and keep kids and pets out.
Hours 2 to 4: document everything before you move it
Photos and video taken now save arguments later. Shoot every room, the waterline on the walls, damaged appliances, and anything you plan to throw out.
Then call your claims agent to start a claim. Ask what they need from you and whether they want to see damaged items before they go to the curb.
Many Texas homeowners find out too late that standard homeowners policies typically don’t cover flood damage. That coverage comes from a separate flood policy, usually through the National Flood Insurance Program.
Hours 4 to 12, get the water out and the air moving
The longer water sits, the more it wicks into drywall, insulation, and wood framing. Getting it out fast is the best thing you can do for the structure.
Pump or extract standing water, then pull up wet rugs and carpet pad. Move furniture off wet floors and set wood legs on blocks.
Open cabinets and closet doors so trapped moisture can escape. Once an electrician clears the power, run fans and dehumidifiers. In Texas humidity, open windows alone won’t dry a house.
“The biggest mistake I see is families waiting to see whether things dry out on their own,” says Andy Sparkman, owner of Lightspeed Restoration of San Antonio North. “Water you can’t see is still soaking your drywall and subfloor. The sooner it’s measured and dried, the less you end up tearing out.”
Hours 12 to 24: stay ahead of mold
Mold moves quickly. The EPA’s guide to mold and moisture says water-damaged areas and items should be dried within 24 to 48 hours to prevent mold growth.
Porous materials are the hardest part. Carpet pad, ceiling tiles, and soaked insulation hold water deep inside, and the EPA notes they may have to be thrown away once they turn moldy.
Watch for a musty smell, swelling baseboards, or drywall that feels soft. Those are signs moisture is still trapped behind the surface.
What to avoid on the first day
- Turning the power back on before an electrician checks wet circuits
- Using a household vacuum on standing water
- Painting or patching walls before they are fully dry
- Tossing damaged items before your adjuster has seen or photographed them
Getting ready for the next storm
Flash floods in this region tend to come back. If you don’t have flood insurance, talk to your agent now.
A new NFIP policy generally takes 30 days to kick in. Buying one when a storm is already in the forecast is usually too late.
Keep a copy of your policy, a walkthrough video of your home, and an emergency contact list in the cloud. The next time a creek rises overnight, your first 24 hours will go a lot smoother.
