Studies of the groundwater flow and quality around the lakes Bredvatten and Lysevatten have shown, that the increased concentrations of aluminum in acid lake water is caused by acid groundwater, and hence of leaching of aluminum into the groundwater. The increased aluminum concentration was later shown to be a major factor in the widespread ecosystem changes occurring in lakes and water systems.

When a similar, but even more pronounced soil- and groundwater acidification occurred via oxidation of accumulated sulfur to sulfuric acid and thereby releasing several soil minerals to the groundwater, a number of regional investigations were carried out on wells and groundwater systems in different provinces in southern Sweden.

The widespread problem with acid groundwater and thus acid tap water, made clear in these studies, shows that several thousand individual households have already acute problems with their drinking water and corroding metalpiping.

The acidification of the groundwater has caused health problems by elevated metal concentrations and economic problems for house owners in an even more pronounced way than acidification of the surface water systems (lakes and rivers). These effects also show how severely affected the lime poor natural ecosystem has become through our own and other countries' airborne acid pollutants.