ABSTRACT: Intensive agriculture in Flanders (Belgium) as elsewhere threatens the quality of groundwater in infiltration areas of abstraction wells. Drinking water companies and the Flemish authorities in particular are very concerned about the short-and long-term quality status of groundwater, particularly in those areas where groundwater is extracted for drinking purposes. To assess the evolution of the water quality in infiltration areas and the effect of N-leaching out of the root zone on the infiltrating water, a research project had been set up. The aim of the project was the development and testing of a methodological approach assessing the fate of N in the zone of influence of groundwater abstraction well fields, based on geohydrological and hydrogeochemical field data and modelling approaches.