Mold Not a Worry in Concrete Cisterns

Learn why mold is not a worry in a concrete cistern. Find out how drywall may foster mold growth, but inorganic materials like cement usually won't grow mold.

LESLIE: Hazel in Minnesota has a question about mold in her cistern. What can we do for you?

HAZEL: What I was wondering, I have a cistern that we used to use but now we drained it and I’m using a water softener. So, do I have to worry about mold getting into this cistern?

TOM: Well, it’s not part of your domestic water system any longer, is it? You’re not using it for drinking water, correct?

HAZEL: It was just like an empty room in the basement, you know,

TOM: Yeah. No, you shouldn’t have to worry about it. If it’s a concrete surface there’s no organic material to grow mold. You know, if it was covered with any sort of a drywall surface or if you converted it from its use, originally, of the cistern to any kind of finished living space then you’d have to worry about it.

HAZEL: No, it’s just like cement blocks, you know.

TOM: Yeah, you really don’t have to worry about it. If it’s not a – if it has no organic material on it you don’t have to worry about it causing mold. It’s dry now, right? It’s all drained out?

HAZEL: Yeah, mm-hmm.

TOM: Yeah. Shouldn’t be an issue, Hazel.

HAZEL: Well, thank you very much.