In the framework of a National Hydraulic Village Program (NHVP) which aim is to equip each village of the Ivory Coast with wells or drillings, a water quality control service was designed, directly on the field, at the Health Rural Sector Bases. The standards of drinkability were revised according to the NHVP constraints. The technics used were adapted to local conditions. Sanitary education was part of the technics used by the field agents. 1,553 wells were analysed by the end of 1978, 17.7% of which were "polluted". Pollution was transient without treatment in 68% of the above cases. The most polluted cases had a rate of fecal coliforms a 1,000 time inferior to the average traditional wells. The drillings were less polluted (10%) than the large diameter wells (24%): in the latter there was a direct correlation between rain fall and pollution. The technical visits by the agents in the villages represented privileged moments of sensibilisation and education of the villagers.