What comes after the water: The science of mold, and how to remediate a flooded home the right way

With cleanup underway across Kerr County, homebuilder Craig Lenard and Alix Seyforth of All Hands and Hearts joined The Lead Live for an in-depth conversation on how to carefully remediate a flooded home — and the science behind why speed and caution both matter is well documented.

“Flood 2.0”: rebuilding the same homes twice

Seyforth and her team at All Hands and Hearts have been living and working in Ingram and Center Point since the 2025 flood, focused on mucking, gutting and mold sanitation. She described the particularly cruel reality of this week’s storm: some of the same homes her team spent the past year rebuilding were decimated again by the July 16 flooding.

Seyforth emphasized that emotional care has to come before physical recovery work — homeowners facing this kind of loss a second time need to be met with patience before anyone starts pulling out wet drywall.

She summarized her team’s operational approach in a simple rule: water plus time equals mold. The immediate priority in any flooded home is getting all wet materials out to dry, followed by bringing in donated fans and dehumidifiers to finish the job.

Asked how a global disaster-response organization decides which crises to respond to, Seyforth said All Hands and Hearts looks at whether local capacity is overwhelmed and whether the community wants outside help. Because the organization was already embedded in the Hill Country from last year’s flood, it was able to begin responding to this week’s disaster immediately.

The 24-to-48-hour window

The science backs up what Seyforth described on air. Mold growth becomes nearly inevitable once building materials stay wet too long. Parham Azimi, a research associate at the Harvard T.H. Chan School of Public Health who studies the link between mold exposure and respiratory health after disasters, says any part of a home exposed to floodwater or leaks needs to be fully dried within roughly a day or two to avoid mold taking hold. “After major storms, we often see spikes in respiratory illnesses,” Azimi said, particularly in homes affected by flooding.

What the research shows about the health risks

The health consequences of mold exposure range from mild to serious. According to the CDC, common symptoms include congestion, asthma flare-ups and skin irritation. Prolonged exposure can lead to more serious complications, including hypersensitivity pneumonitis — a rare lung inflammation — and illness linked to mycotoxins, which has been associated with neurological damage, liver disease and kidney dysfunction. Both Lenard and Seyforth emphasized on air that airway protection is non-negotiable for exactly this reason: respirator masks are what stand between a person doing cleanup work and highly toxic mycotoxin exposure.

Research following past disasters backs up the danger. After Hurricane Katrina struck New Orleans in 2005, outdoor mold spore concentrations in flooded areas were roughly double those in non-flooded areas — and indoor concentrations were measured even higher than that. A separate study examining both Katrina’s aftermath and 2007 flooding in the United Kingdom found that water damage accelerated both mold growth and respiratory allergies in affected homes. Homes don’t need to have been fully submerged to create a problem — persistent dampness alone is enough to spur respiratory issues in occupants.

Children face particular risk. Research on respiratory health in young children across dozens of Canadian communities found that all measured respiratory symptoms — including asthma, bronchitis, eye irritation and cough — occurred more often in homes with mold or dampness.

Seyforth’s own guidance reflects this research directly: she strongly advised families against trying to live inside a home with mold exposure while cleaning it, urging them instead to seek emergency local housing until the work is done.

A warning about scams

Kelly Hagemeier of Kerr Together and Lead founder Louis Amestoy both used the segment to warn residents about a predatory pattern already emerging in the county: unvetted contractors circulating in flood-hit neighborhoods offering quick cleanup quotes at steep prices. Both stressed that professional-grade “muck and gut” work and sanitation labor is available completely free through trusted, vetted organizations, including All Hands and Hearts, Team Rubicon and Texans on Mission. Residents are urged to be patient and avoid rushing into a paid contract before checking whether free help is available.

Displaced families, volunteers, and anyone needing dehumidifiers or free cleanup help are directed to go in person to the Kerr Together Disaster Resource Center, 98 Coronado Dr. N.

Practical guidance for cleanup

Building on the science and on-air guidance, cleanup recommendations from the CDC, EPA, FEMA and NIH include:

• Wearing, at minimum, an N-95 respirator, goggles and protective gloves; a half- or full-face respirator is recommended for extended mold cleanup work
• People with asthma or other breathing conditions, weakened immune systems, or children should avoid mold-damaged spaces entirely
• Never using bleach in a closed space — open windows and doors first
• Discarding drywall and insulation contaminated by sewage or floodwater, since these materials generally can’t be cleaned and salvaged
• Fixing any leaks in roofs, walls or plumbing as soon as possible, since mold will return if the moisture source isn’t addressed

This is a developing story and will be updated.