This study presents a simple method aiming to help water authorities and decision-makers to decide which pesticides should be selected for residue analysis in receiving water bodies. The method is based on the pesticide consumption records together with intrinsic properties of pesticides, such as solubility, DT50, K-OC and K-D. It is independent from local soil and climatic conditions and can easily be used in any drinking water reservoir covered by agricultural areas. The method was applied to drinking water reservoirs of Istanbul where 45 different types of pesticides were used. The total number of pesticides, which have to be analyzed, was 18. Using this analytical method, two pesticides marked as "the ones which must be analyzed" were detected and none of the eliminated pesticides was found. The detected concentrations were found to be below the limits of EU drinking water standards (0.1 mug/l).