In 1996 the Environmental Agency first surveyed groundwater contamination and found more than 1200 sources of pollution in England and Wales. The main pollutants are pesticides (atrazine and simazine in particular).

The European Commission has set Maximum Admissable concentrations for pesticides in drinking water at 0.1 part per billion for any one pesticide and 0.5 ppb for total pesticides.

In Belgium, Denmark, France, Germany, Netherlands and UK between 5% and 10% of groundwater resources regularly contain pesticides in excess of 0.1 µg/l.

Groundwater pollution poses a mounting threat to environmental sustainability and public health in Europe. Many countries are becoming increasingly dependent on groundwater for their drinking water supplies.