Mold in St. George homes
St. George is dry most of the year, but mold still grows where water collects indoors. In a desert home, mold almost always points to a specific water source: a leak, a flood or a cooling system.
Floods and storm water
In January 2005, a rain-on-snow event caused severe flooding along the Santa Clara River in St. George, with damage to homes estimated at $300 million. Summer storms can also push water into homes through roofs, windows and doorways. Water that soaks drywall, insulation or flooring needs to be dried within a day or two. Dry outdoor air helps, but materials inside walls and under floors stay wet until they're opened or actively dried.
Plumbing leaks
The City of St. George says most water in Southern Utah is hard. Hard water scales fixtures and valves, and scale can keep valves from sealing; slow leaks under sinks, behind dishwashers and at water heaters are a common mold source. Look under sinks regularly, and check the floor around the water heater, washing machine and refrigerator.
Cooling systems
A reading of 117°F at the St. George cooperative weather station on July 10, 2021 tied Utah's all-time maximum temperature record. Air conditioners run for months, and their condensate drains can clog and overflow into ceilings and closets. Evaporative coolers add moisture to the air by design; a cooler that's too big for the house or runs with closed windows can raise indoor humidity enough to grow mold. Ask an HVAC technician to check condensate drains and cooler operation.
Attics and roofs
Roof leaks in a dry climate can go unnoticed for months, because a small drip dries out between storms while slowly soaking insulation and wood. After a heavy storm, look in the attic with a flashlight for stains, damp insulation or daylight around vents and pipes. On tile roofs, failing underlayment lets water through even when the tiles look fine.
Testing
Visible mold doesn't always need testing. Testing helps when you smell mold but can't find it, or to show cleanup is complete. Ask an inspector what they'll test and why. Be cautious if the same company tests and remediates.
Remediation
For more than a small area, remediation should include containment, removal of moldy porous materials, cleaning and drying. Ask what the company's containment looks like, how they'll protect the rest of the house, and how they'll decide the job is done. Most of all, ask them to identify the water source. Without fixing it, the mold comes back.
Before you hire
Get a written scope naming rooms, materials and the containment plan. Ask whether clearance testing is done by an independent party, and what warranty, if any, they offer.