The problems in dug wells are mostly caused by bacteria, while drilled wells suffer from contamination with minerals such as uranium and radon.
Meanwhile there are some 450,000 dug wells and 160,000 drilled wells in Finland.
Hydrogeology expert Kirsti Korkka-Niemi from the University of Helsinki says that over half of them have some problems with water quality. In the worst case scenario, contaminated water can pose an actual health risk.
Finland's environmental administration recommends testing well water every three years, especially if there are small children in the family that uses the well.
