In addition to killing wildlife, pesticides used in the EU also act to contaminate vital water resources. According to a recent study conducted on behalf of the European water industry, pesticide contamination is most acute in lowland river areas, particularly in Belgium, France, Netherlands and the UK. In all four of these countries, a high proportion of the resources contain residues above the legal threshold, often by a significant margin. In Germany, Denmark and the Netherlands too pesticide pollution in excess of legal limits now affects up to 10% of all groundwater resources. Unsurprisingly, several of the contaminants which most regularly cause water pollution problems across Europe are ranked among those pesticides most commonly used within the EU (the weedkillers: atrazine, isoproturon and MCPA).

With substantial levels of pesticides now contaminating European water resources, utilities companies across the EU are forced to spend large sums on water treatment every year. Estimates suggest annual investments of €24.4 million in the Netherlands, €130 million in Germany, and €170 million in the UK. Ultimately these costs are passed on to consumers.