Basement water seepage can be an ongoing issue that sometimes becomes just a fact of spring. Water from saturated ground can find it's way in through just about any crack or seam in a basement's floor and foundation. Sometimes it can even soak directly through solid concrete. If rising ground water becomes trapped under the floor, it can build "Hydro-static" pressure, resulting in cracking and heaving.
In home radon levels are a serious concern. Radon originates from deep uranium deposits. When radon's decay products are inhaled they release Alpha, Beta and Gamma radiation directly into your lungs. If you spend a lot of time in your basement and especially if you have a basement bedroom, radon levels should be checked.
Radon is second only to smoking in national lung cancer risk statistics. However, radon levels can usually be reduced easily and at a reasonable price.
Although radon gets most of the attention, it's not the only soil gas you may encounter in a basement. There can be methane, hydrogen sulfide, pesticides, emissions from old land fills or chemical spills. Water vapor is a soil gas as well. Humidity can be lowered with a good radon mitigation system, possibly eliminating the need for dehumidifiers.
The money saved on running dehumidifiers, will most likely outweigh the $100 a year or so in electricity to run a mitigation system. And you may be extending your or a loved ones life. According to the EPA the most effective Radon Mitigation method isSub-Slab Depressurization.