Groundwater is the primary source of drinking water for small municipalities and individuals. However, groundwater can be polluted by almost any land use. Consequently, many governments have acquired groundwater information in the aim of protecting the resource. Nevertheless, the resulting data are often ill-fitted to planning needs. In a previous study, a method was developed to help planners interpret hydrogeological data. It combines land planning and hydrogeological data through multicriteria analysis, in order to obtain groundwater contamination risk maps. The method proved efficient and useful. However, it could not be easily implemented by land planners, who do not always have training with these types of data and geographical information system (GIS). This paper presents how the method was integrated into a web-based interface called Aménagement du Territoire et Eau Souterraine (ATES). ATES allows planners to view groundwater basic maps, evaluate the present contamination risk for groundwater, and analyse new planning scenarios. ATES also suggests mitigation measures and offers tools to discuss the possible solutions. The tool has been developed, tested and validated with land planners. To our knowledge, it is the first geo-informatics tool developed especially for planners that aims at facilitating the incorporation of groundwater into planning. Moreover, an innovative approach called MACBETH was used for data aggregation, a novelty in groundwater management and spatial data integration.