The Food Quality Protection Act of 1996 (FQPA) requires that all tolerances for pesticide chemical residues in or on food consider anticipated dietary exposure and all other exposures for which there is reliable information. Drinking water is considered a potential pathway of dietary exposure to pesticides. Because drinking water for a large percentage of the population is derived from public water systems which normally treat raw water prior to consumption, the impact of water treatment on pesticide removal and transformation should be considered in drinking water exposure for risk assessments completed under FQPA. Treated drinking water for the purpose of FQPA exposure assessment will be defined as ambient ground or surface water which is either chemically or physically altered using technology prior to human consumption. Therefore, the objectives of this science policy paper are to: (1) present a preliminary literature review on the impact of different treatment processes on pesticide removal and transformation in treated drinking water derived from ground and surface water sources; and (2) describe how the Office of Pesticide Programs (OPP) will consider the impacts of drinking water treatment in drinking water exposure assessments under FQPA.