Fecal pollution of water from a health point of view is the contamination of water with disease-causing organisms (pathogens) that may inhabit the gastrointestinal tract of mammals, but with particular attention to human fecal sources as the most relevant source of human illnesses globally. Ingestion of water contaminated with feces is responsible for a variety of diseases important to humans via what is known as the fecal-oral route of transmission.