Douglas County’s drinking water comes primarily from the Authority's 1.2 billion-gallon Dog River Reservoir. How does that water get from the lake to your faucet?
We start with what we call raw water. At the reservoir intake station, debris such as fish or sticks that could damage plant equipment is removed before water is pumped to the Bear Creek Water Treatment Plant.
As water enters the plant, it is treated with various chemicals, including chlorine, alum, and lime. They kill disease-causing organisms, adjust the water’s pH and prevent it from having any taste or smell. They also help get tiny particles in the water such as silt to stick together so that they become so heavy that they settle out in a process called coagulation.
Water then moves through a series of chambers, where it is stirred and directed over and under a series of boards. That evenly distributes the chemicals and initiates the coagulation process. As the tiny suspended impurities begin to stick together and grow heavy, water is held in a sedimentation tank so those particles, called floc, can settle out.
You’re almost through! Water then moves though a filter composed of coal, sand and stone that removes any remaining solids, ensures clarity and further disinfects the water. The filtered water then gets one last shot of chemicals, including chlorine, for final disinfection; lime, to adjust pH; phosphates, to prevent corrosion of the pipes that carry water to your house; and fluoride, which strengthens your teeth.
Your finished water then is held in the Authority’s 3 million gallon clearwell at the plant, so the chemicals can mix evenly mix before water is pumped into the distribution system and eventually your home! Water not used by homes or businesses goes into the Authority’s six water towers. Those reserves pressurize the system so that your taps run at full flow. They also make sure the community has water to fight fires and to meet demand in unusual circumstances, such as during a power outage or on a hot day when demand is extremely high.