About 85% of the potable water in the Lewiston system comes from the Clearwater River. It is then treated in a conventional water treatment plant. This consists of clarifying the raw or river water by adding chemicals that coagulate the impurities and then these are settled in a basin. Finally, the water is passed through a mixed media filter. Sodium Hypochlorite is added for disinfection and to maintain a residual in the distribution system.
Fluoride is added to the water as an aid to dental decay. The pH is adjusted to be more neutral to prevent mineral depletion from the piping.
The remainder of our water comes from wells. Lewiston has six wells. Three are used primarily for irrigation of parks, the cemetery, and a golf course. Three are utilized for domestic needs.
The average daily production annually is 4.1 million gallons per day (mgd). This may peak in the summer months to about 7.5 to 8.5 mgd. The average flow in the winter months is about 1.5 mgd.
Our system contains six reservoirs and two clear wells that have a capacity of about fifteen million gallons. This is in reserve on a continual basis for domestic, commercial and fire flow use as each day the reservoirs are filled.