Mold remediation in St. Charles County, Missouri: O'Fallon, St. Peters and Wentzville

Does St. Charles County help with mold cleanup?

No. St. Charles County’s Division of Environmental Health and Protection says it does not perform indoor air testing or assist with mold cleanup. You can report a concern for mold growth in a county building to your municipality or the County’s Community Development department. Cleanup is up to the owner and a contractor.

That matters because many owners call the County first. The answer is a referral, not a crew. If you find mold in O’Fallon, St. Peters, Wentzville or the city of St. Charles, plan to hire a company yourself. AES offers mold remediation and mold inspection from its St. Louis office.

Why do new homes in O’Fallon and Wentzville get mold?

Moisture. Mold needs water, not age. Only 9.2% of O’Fallon homes and 9.9% of Wentzville homes were built before 1980, so these are mostly newer houses. A leak or a wet basement feeds mold in any house.

Place figures are 2024 American Community Survey 5-year estimates. The county row is the 1-year estimate for 172,400 housing units, so compare loosely. St. Peters shows a bigger 1970s share than its neighbors, at 25.3% before 1980.

Common causes include a failed supply line, a clogged drain, a roof leak and water that finds its way through the foundation. The fix always starts with the water. Read our guide to mold after water damage.

How big a mold problem needs a professional?

EPA draws the line at 10 square feet. It says that if there has been a lot of water damage, or mold growth covers more than 10 square feet, you should consult its guide for larger buildings. Hidden growth, sewage water and repeat outbreaks also call for a pro.

Ten square feet is a patch about 3 feet by 3 feet. Measure what you can see. Then look for what you cannot: behind drywall, under carpet pads and around plumbing. Our post on mold over 10 square feet explains how to size a patch.

A trained crew limits the spread of mold spores with containment, cleans the air with a HEPA filter and removes damaged material. Learn what mold remediation means in the trade.

Do basements and foundations matter in St. Charles County?

Yes. Water and gas both use the same cracks. The County says radon can become a problem indoors by seeping through cracks and gaps in foundations, drains or other openings. Water finds the same paths, so a damp foundation is a mold warning.

We do not have a county figure for how many homes have basements, so we do not claim one. Check your own: look for stains at the base of walls and a musty smell. AES describes its moisture barrier as a liquid applied before flooring to prevent moisture from penetrating the floor. See moisture barriers.

For water damage, the fire and water restoration page covers the first steps.

What does mold remediation cost and how long does it take?

AES publishes one range: “Prices typically range between $1500 to $10,000 for a home which is showing visible signs of mold.” AES adds that “1 to 5 days is the normal timeframe expected to complete most average jobs.” Each job differs, so AES quotes by address.

Size, material and the water source drive the price. A small bathroom ceiling costs less than a finished basement with wet drywall. See mold remediation costs and our mold remediation cost and timeline guide for the factors. A quote request takes a few minutes at /contact.

Should I test for mold first?

Usually not when mold is visible. A test helps when you smell mold but cannot find it, or when you want proof a cleanup worked. AES offers mold inspection, and our glossary explains mold inspection in plain terms.

Be careful with free test offers and cheap swabs. A result with no plan behind it just starts an argument. Ask what the test will change. If you can see growth over 10 square feet, go straight to a plan, a quote and a fix for the water. For visible black growth, see black mold remediation and home mold removal.

How far is the AES office from St. Charles County?

AES works from 3100 Gravois Ave in St. Louis. O’Fallon (100 S. Main St.) is about 36.8 miles away, about 51 minutes without traffic. Main Street in the city of St. Charles is about 25.9 miles, about 38 minutes. These are OSRM free-flow estimates, so allow more at rush hour.

AES says it serves St. Louis, St. Charles and Columbia, Missouri, and projects within 300 miles of St. Louis. For the city of St. Charles, including demolition permit steps and asbestos rules, see St. Charles, Missouri. For nearby work, see St. Louis County.

Which AES services fit a St. Charles County mold job?

Mold jobs often need more than a cleanup. A leak must be fixed, wet materials removed and the floor protected.

• Mold remediation removes mold-contaminated building materials.
• Mold inspection looks for hidden growth.
• Home mold removal covers houses.
• Moisture barriers go under new flooring to prevent moisture from penetrating it.
• Fire and water restoration handles water damage first.

AES serves residential and commercial customers. See commercial mold remediation for larger buildings.

How do I get a quote?

Call (314) 865-2662 or send our quote form. Give us your city, where you found mold, how big it looks and what caused the water. Photos help.

Next step

Call (314) 865-2662 or use the quote form with your St. Charles County address. Start with the mold remediation page.