Diffuse pesticide pollution is a problem for the environment, but it also presents a challenge for water companies managing treatment infrastructure to produce potable water. The legal framework for this context has three main components: that dealing with pesticides and pesticide use, that dealing with environmental water quality and that dealing with drinking water quality. The study set out to identify, interpret and assess the impact of the legal framework related to this challenge. The study found that the current policy and legislation do not provide a coordinated legal framework and some changes are warranted. For example the Water Framework Directive (WFD) sets environmental quality standards for some, but not all, pesticides. Article 7 provides special protection of water bodies used as sources for drinking water supply, but it is not clear whether the UK will achieve full compliance by 2015. This is a problem for water companies planning investment, because the WFD and Drinking Water Directive remain legally distinct. Further uncertainty arises from the application of Regulation (EC) 1107/2009 and the extent that restricted availability of pesticides will drive changes in agricultural practice and pesticide use.