GEF

Unit 3  |  Water Use and Human Water Systems 78 dramatically with widely available household water. Sewer sys- tems carry away and treat waste that used to be responsible for regular outbreaks of cholera, typhoid, and other deadly infectious diseases. The basic functions of effective household water systems include protection of water sources from contamination, water distribution, treatment, and sewage disposal. In developed countries, engineers have learned how to meet these needs with centralized water systems managed by local or regional agencies. In rural areas, a portion of residents are not con- nected to community water systems, relying instead on private wells and septic systems. In many cases, users can be unaware of the source of their household water and the systems that deliver water to their homes and carry away waste. In the U.S., there are more than 600,000 miles of sewer pipes.