Often, condensation — not a leak — is the source of the moisture, Collier said.
“The bathroom fan is a big part of keeping the moisture level down in the bathroom,” he said. “If there isn’t one, put one in. If there’s a small one, put in a bigger one or use it more.”
Opening the bathroom window also helps, as does more frequent cleaning, according to the EPA.
Collier also suggests using a squeegee to wipe down the shower walls.
There are many products available for cleaning mildew and mold, but homeowners also can mix their own. A bleach solution that CDC says should be “no more than 1 cup of bleach in 1 gallon of water” can be used to clean and kill mildew.
“For the typical homeowner, they would scrub it down really well with bleach water and then they should seal the grout, seal it once a year or so to keep it water tight,” Collier said.
Wear protective gloves while cleaning. The CDC also recommends protective eyewear.
If you can’t get rid of the mildew with bleach, you might have to dig out the grout and replace it, Collier said.
For those looking for an environmentally friendlier alternative to bleach, Collier said one of the products that mold experts recommend is Concrobium, which also can be used as a fog if a whole room is affected.
It’s not just bathrooms where you’ll find mold or mildew.
“Sometimes people find it in closets where there’s limited air circulation, and where maybe there’s a cool wall and it’s humid,” Collier said.
Or there could be condensation around heating ducts, and you’ll find a moldy patch on the ceiling.
Moisture from roof leaks also can lead to growth of mold and mildew.
If you paint over mildew, the paint likely will peel. Birenbaum says there special primers that inhibit mold growth.