A leak doesn’t have to be dramatic to cause mold. A slow drip under a sink, a roof leak that stains a ceiling, or a basement that took on water in a storm can all do it. The EPA explains that mold spores are always present indoors, and all they need to grow is moisture. That is why the EPA advises drying water-damaged areas and items within 24 to 48 hours.
If the water has already been there longer than that, or you aren’t sure, here is how to check, what to do next, and when to call for help.
What does mold look and smell like?
CDC says mold can appear as spots of many different colors and can have a musty smell. The CDC’s workplace health researchers at NIOSH describe visible mold in more detail in their dampness and mold assessment tool. It shows up as patches or spots colored differently from the material underneath, typically gray, brown or black. It can look fuzzy and may smell musty or earthy.
Smell can be the first clue. The EPA’s mold course says damp or musty odors suggest that water is or was present and mold growth is likely.
What signs point to moisture I can’t see?
| What you notice | What it can mean |
|---|---|
| Musty smell, no visible mold | Mold may be growing behind a wall, under flooring or in ductwork |
| Water stains or discoloration | Water reached that spot, now or in the past |
| Peeling paint, rust, warping or crumbling material | Signs of water damage, according to NIOSH |
| Water beads or condensation | Visible moisture, which NIOSH counts as a sign of dampness |
| Materials that stayed wet more than 48 hours | Mold growth becomes likely, per EPA guidance |
| Allergy or asthma symptoms that flare at home | CDC says mold may still be present |
The EPA says a moisture meter, a handheld tool that measures water inside materials like drywall, wood, brick and concrete, can help find hidden wet areas. It can also show whether drying is working.
Where does mold hide after a leak?
The EPA lists the usual hiding places.
- The back side of drywall, wallpaper and paneling
- The top side of ceiling tiles
- The underside of carpet and carpet pads
- Inside walls near pipes, and in pipe chases (the hollow spaces plumbing runs through)
- Inside ductwork and around condensate drain pans
- Walls behind furniture
Bathrooms, laundry rooms and basements are common spots in homes. Vinyl wallcoverings and wood paneling can trap moisture behind them, so a wall can look fine on the front while the back is moldy.
For Chicago basements, carpet is worth a close look. CDC advises against carpet in high-moisture areas like basements and says to remove soaked carpet and upholstery that can’t be dried right away.
Be careful about opening things up. The EPA warns that disturbing hidden mold, such as by peeling back wallpaper, can release a large number of spores, and suggests an experienced professional when you suspect hidden mold.
Should I test for mold?
Usually not. CDC does not recommend mold testing. It says health effects vary from person to person, testing can be expensive, and there are no set standards for how much mold is acceptable in a home. The Illinois Department of Public Health says that if you can see or smell mold, testing is usually not necessary.
The EPA notes that sampling can be useful in a few cases, such as when the source is unclear or health concerns exist, and that trained professionals should do it.
Can I clean it up myself?
Sometimes. The EPA says most people can handle an area of about 10 square feet or less, roughly a 3-foot by 3-foot patch. IDPH says a professional should clean up anything larger.
Call a professional for these situations, based on EPA and CDC guidance.
- Mold covers more than about 10 square feet, or there was a lot of water damage
- The water was contaminated, such as a sewer backup
- You suspect mold in the heating or cooling system (EPA says not to run it)
- Mold may be hidden inside walls or under floors
- The person who would do the work has asthma, breathing problems or a weakened immune system (CDC says they should stay away from moldy areas)
If you do a small job yourself, CDC’s cleanup guide says to wear at least an N95 respirator, non-latex gloves and goggles without vent holes. Keep children out of the work area.
- Fix the leak first. EPA says mold will likely return if the water source isn’t fixed.
- Scrub hard surfaces with detergent and water, then dry them completely.
- Remove porous materials like ceiling tiles and carpet that have grown mold, since they may have to be thrown away.
- Go easy on bleach. EPA does not recommend routine use of bleach during mold cleanup. If you do use it, CDC says to use no more than 1 cup of household bleach per gallon of water, and never mix bleach with ammonia.
- Leave the fans off if mold is already growing. CDC says they can spread it.
- Skip the paint. Painting or caulking over mold won’t stop it.
How do I know the problem is really fixed?
The EPA says cleanup is complete when the moisture problem is fixed, visible mold and musty odors are gone, later checks show no new water damage or regrowth, and people in the home have no symptoms. CDC recommends keeping indoor humidity no higher than 50 percent.
Will insurance cover mold from a leak?
It depends on the cause. Triple-I says mold is generally not covered by standard homeowners policies because it is treated as a maintenance issue. If the mold resulted from a covered event, such as a burst pipe, the cost of removing it may be covered. Call your insurance professional if you think that applies.
How do I choose a mold remediation company in Illinois?
Illinois is changing how mold remediation companies are tracked. IDPH says the Mold Remediation Registration Act will require remediation providers to register and show financial responsibility once its rules are adopted. IDPH also notes that mold certifications come from third-party groups such as ACAC, IICRC and NORMI, not from the state, and that it does not license mold assessors. The EPA suggests choosing a contractor with mold cleanup experience, checking references, and asking them to follow EPA guidance or industry standards such as those from IICRC.
When to call a restoration company
Call us when you see or smell mold after a leak, when the area is bigger than a small patch, or when you aren’t sure how far the water went. A person answers 24/7. We ask what happened, where the water came from and how long things were wet. Then we send a crew to find the moisture, stop it from spreading and start mold remediation, along with any water damage restoration the leak still needs. We photograph and record what we find and what we remove, so your insurance claim has the details.
If there is ever a gas smell, sparking or another emergency, leave and call 911 first. When you are ready, contact us.