This work analysed domestic water use and environmental health in East Africa and charted any major changes or trends since the last study in 1972. They also investigated the links between the prevalence of diarrhoea and the nature of water supplies, sanitation facilities and hygiene behaviour. They surveyed over 1000 households in 33 sites in Uganda, Tanzania and Kenya in 1997. The type of water source, the amount of water used for cleaning and bathing, ownership of a latrine or other sanitation facility and hygiene practices are important determinants of the incidence of diarrhoea. Tropical Medicine and International Health 2002;7:750-756.