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France is rich in groundwater. It has many aquifers with renewable resources which are estimated at 100 billion m3/year, of which 3.5 billion m3, or 60% of the water used in France for human consumption, are withdrawn each year. This practice is justified by the often naturally pure quality of the water and by the regularity of the resource. Nevertheless, free aquifers, in spite of natural physical and geochemical barriers, are not sufficiently protected from anthropic surface contamination and when pollutants reach them, the consequences are never negligible, be it from a sanitary, economic or natural heritage point of view. The most extensive pollution is nitrate contamination. Nitrate concentrations have been increasing constantly over the last 30 years and in some regions have gone over the critical threshold of 50 mg/l which is the European standard, and concentrations of 100 mg/l have been measured in some places. The gravity of other types of pollution--mining, industrial or domestic--is determined by the mineral or organic products involved. The cumulative effect of all of this pollution is serious from various standpoints: from an economic and environmental point of view because aquifers contribute to the maintenance of aquatic life, and for our natural heritage because of the long-term degradation of vast aquifers in some very urban and industrial regions. We might, therefore, question the possible long-term use of aquifers as a source of drinking water.