ENOLA, Pa. (WHTM) – Some schools in Enola, Pennsylvania were closed for the third day in a row Thursday as the district waited for test results in two buildings after finding mold in two others.

Administrators decided to close and test the middle school and West Creek Hills Elementary after finding high spore counts in the high school and East Pennsboro Elementary.

Chances are, whether the tests come back positive or negative, there’s at least a little mold in the other two — because there’s mold everywhere.

“When I go into a basement, I know what to look for and where to look,” Keith Bailey, chief inspector for Mold Erasers, said.

Jared Halvorsen’s basement in Harrisburg is no different.

“It doesn’t have to be black to be mold and it doesn’t have to be black mold to be bad,” Bailey said during an inspection Thursday.

The fungus needs three things to grow: humidity, oxygen, and food. Halvorsen’s basement has plenty of all of them.

“That is aspergillus penicillium,” Bailey explained to the homeowner, shining a flashlight on a white coating collecting on a floor joist. “It’s the most common mold found in central Pennsylvania.”

Mold is so common, your house definitely has some.

“It’s humanly impossible to live in a mold-free environment or to be in a mold-free environment,” Bailey said.

But some is okay. The key is knowing where to look — anywhere moisture collects, open floor drains, wherever something is directly up against a concrete wall.

“When you have cold water lines running through a warm basement,” Bailey explained, “condensation on the lines is going to increase humidity in the structure.”

Humidity above 50 percent is great for mold, and fireplaces can also let moisture in.

“You won’t have standing water, it’s not going to be flood-type issues,” he said, “but it’ll elevate the humidity in the structure.”

Oh, and don’t vent your dryer into your basement. It might save on energy bills, but that’s a real good way to bump up the humidity.

Halvorsen had his dryer vented that way. Bailey found mold colony after mold colony.

Unless you’re allergic, though, the mold in your home likely won’t bother you — as long as you don’t notice it.

“It is everywhere,” Bailey said, “but once you can see it, it’s probably already at levels that you should have it addressed.”

That’s what worries Halvorsen.

“You know,” he said, “I’ve got seven people living in this house. They don’t need to be suffering from just living here. That’s kind of the opposite of what a home is, right?”

One last tip: Don’t use bleach to clean the mold. It just doesn’t kill the fungus.