Some 60% of all infant mortality is linked to infectious and parasitic diseases, most of them water-related (161). In some countries water-related diseases make up a high proportion of all illnesses among both adults and children. In Bangladesh, for example, an estimated three-quarters of all diseases are related to unsafe water and inadequate sanitation facilities. In Pakistan one-quarter of all people attending hospitals are ill from water-related diseases (5).

Providing clean supplies of water and ensuring proper sanitation facilities would save millions of lives by reducing the prevalence of water-related diseases (174). Thus, finding solutions to these problems should become a high priority for developing countries and assistance agencies.

While water-related diseases vary substantially in their nature, transmission, effects, and management, adverse health effects related to water can be organized into three categories: water-borne diseases, including those caused by both fecal-oral organisms and those caused by toxic substances; water-based diseases; and water-related vector diseases (14, 216) (see Table 2). Another category—water-scarce (also called water-washed)—diseases consists of diseases that develop where clean freshwater is scarce (216).