All of the more than 37 billion gallons of water delivered by Tucson Water to its 709,000 customers each year is groundwater pumped from area aquifers. About 90% of our drinking water is a blend of groundwater and Colorado River water. In its 375-square-mile service area, Tucson Water operates 175 groundwater wells, 20 water reservoirs of 1 million gallons or more capacity, 3,500 miles of pipeline, and hundreds of booster stations and pressure control valves that give Tucson Water maximum flexibility in water delivery.
Water may be pumped from wells directly into the distribution system or into large transmission lines for delivery elsewhere in the community. During the night, or when customer demand is lower, water is pumped to reservoirs for storage for later use. The water is chlorinated at the wells and monitored in reservoirs and at other sites in the distribution system. If necessary, additional chlorine can be added at many of these sites.