Safe moisture level

[stroo]

I understand no moisture is optimal but does anyone know what a safe moisture percentage would be? I picked up a couple hygrometers and have been measuring different parts of my basement and it seems to be 58-60% humidity right now. Do you think that is a safe level or should I crank up the dehumidifier to run more?

[Hawgrider]

About 40% above 20 degrees. Below 20 degrees less humidity.

If that humidity stays too high you could get a nice bloom of black mold.




http://healthandenergy.com/mold_prevention.htm
Indoor Humidity

Molds do not require liquid water to grow. They only require relative humidity levels from 65% to 99% at the surface on which they grow. If you keep the humidity low enough, you can prevent mold growth. Maintaining relative humidity below 50% inhibits mold and mildew growth, dust mite infestations, and bacteria. This lower relative humidity also reduces the out-gassing of volatile organic compounds (VOCs). In colder climates, wintertime humidity levels must be even lower — generally, 25% to 40% (to prevent condensation on windows).