History of the Aquifer
By 1908 construction by the Spokane Valley Irrigation District to build irrigation from the aquifer had finished, and the aquifer became the main source of drinking water for Spokane instead of the Spokane River. The aquifer is now the only source of water for most people in Spokane County, Washington and Kootenai County, Idaho. Studies in the early 1900s found the water from the aquifer to be some of the cleanest in the world, but later studies found the aquifer contained pollution. A mixture of the permeable flood deposits and a thin topsoil layer made the SVRP aquifer susceptible to pollution.
In the 1970s users of the aquifer began taking steps to protect and clean the SVRP aquifer. The SVRP aquifer was designated as a sole source aquifer by the US Environmental Protection Agency, which contributed the the management and regulations of the aquifer