The study of the literature relative to the impact of cover crops on nitrate leaching, and hence their primary role as “nitrate-trapping” catch crops in annual cropping systems, reveals a lack of data relating to certain regions in France. The same is true concerning their impact on other variables, such as the water balance or the yield of the next crop. However, since the planting of cover crops has become compulsory in all vulnerable zones since 2012, it is of the utmost importance to assess how effective they are in terms of reducing the nitrate concentration of drainage water, as a function of the soil and climate context in a broad range of French conditions. By doing so, it will be possible to optimize the associated management technique and identify situations in which their use may have negative consequences on the next crop and, potentially, on groundwater recharge.