The City of Moscow receives its water entirely from groundwater sources. This means that rather than being supplied with water from a lake or reservoir, we pump water from two main underground aquifer systems, the Wanapum Aquifer System and the Grande Ronde Aquifer System. Contrary to popular myth, aquifers are not underground lake or river systems. Rather, the water in the aquifer systems is located in the cracks, pores, and fissures of the basalt and sediment layers.
The Wanapum Aquifer System is the shallower aquifer system of the Palouse Basin and is found starting about 60 feet below the surface. This system supplies about 30% of the City of Moscow's water. Wanapum well levels in Moscow area wells fluctuate some due to pumping and recharge but appear to be fairly stable.
The Grande Ronde Aquifer System is the deeper aquifer system of the Palouse Basin and is generally found at depths below 300 feet, if it is available at all. This system is the main source of water for the City of Moscow and virtually the only source for Pullman and Washington State University.