The purpose of this paper is to analyze the implication of wetland construction for the cost-effective design of a pesticide charge. A model is developed in order to show that, for a given target, the introduction of wetland construction can reduce overall abatement costs and can lower the input charge asked to the farmers. This result remains true as long as the cost of constructing a wetland is not too high. A numerical illustration is carried out in order to simulate pesticide regulations in a wine catchment in North-East of France