Legislation emanating from the European Community is establishing pressures to take action to reduce the level of nitrates in water, and the principles established towards environmental management indicate an emphasis on prevention rather than treatment. This paper analyses three possible approaches by means of controls on fertilisers, on nitrate leaching and on land use. These are incorporated into a linear programming model of a catchment in Cambridgeshire. The results indicate the superior cost‐effectiveness of controls over leaching and the severe impact which taxes would have on farm incomes. A system of permits on land use is found to be relatively cost‐effective and to offer an administratively feasible alternat