Water

Before urban development, safe drinking water could be taken directly from lakes and rivers. But with the growth of cities and the increase in population density, natural water systems became overwhelmed. Receiving streams not only became polluted, but health problems resulted as diseases were spread from upstream dischargers to downstream users. Additional treatment of water for human consumption became necessary. Polluted waters also required treatment to protect both aquatic life and the recreational value of rivers and lakes.

As a result of air and water pollution, water taken from rivers, lakes, and some groundwater must be purified before use as drinking water. Egyptian wall inscriptions indicate that water treatment was performed as early as 2000 B.C. Modern treatment procedures, including filtration and coagulation, were developed in the 17th century. Treatment is designed to remove organic and inorganic contaminants, as well as disease-causing organisms.

Groundwater is a common source of drinking water. Most groundwater is naturally filtered as it passes through layers of the earth into underground reservoirs known as aquifers. Water that suppliers pump from wells generally contains less organic material than surface water. The most common drinking water treatment is disinfection. Most water suppliers add chlorine to kill bacteria and other germs.

Water can be pumped from wells dug below the level of the water table. The water supply for the Town of Denton is provided by a well system that uses groundwater from the Piney Point Aquifer. After being disinfected, the water is pumped to one of the 3 storage tanks until delivered to the users through a distribution system made up of pipes, valves, meters, and fire hydrants. Storage tanks ensure that sufficient water is available to meet surges in demand.

The greatest challenge to water treatment operators is protecting the quality of the drinking water in the distribution system. The water must arrive at the users’ homes at an acceptable temperature, free of disease-causing organisms, and without objectionable odors, tastes, colors, or other contaminants. Water treatment facility operators monitor each process for signs of malfunction and routinely test for changes in pH, chlorine residual, and alkalinity.

Access to safe, reliable drinking water is a priority in every community and a right of every citizen. In 1974, Congress passed the Safe Drinking Water Act to ensure that drinking water supplied to the public is safe. Check AWWA.org for more information. The EPA requires that every community water supplier provide an annual report to its customers. Visit http://www.epa.gov/safewater/