USGS Washington Water Science Center
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The rapid growth of population in the Tacoma-Puyallup area in Pierce County has placed increasing demands on the ground-water resource. Most domestic water needs are met by wells completed in the several hundred feet of glacial deposits that underlie the area, and about 9,000 persons are served by a single spring on the southwestern side of Puyallup. Most of the population relies on individual septic tanks.
Health officials in Puyallup and Pierce County are concerned that the high density of septic tanks and a local landfill could lead to excessive concentrations of nitrate, chloride, and bacteria in the ground-water system and in the drainage area of the spring.
To help local officials develop a better understanding of the characteristics and quality of the area’s ground-water resource, the USGS is describing the water-bearing and confining units, determining the quantity of water, and determining the quantity and fate of recharge to the ground-water system. The study also includes assessing the general water chemistry of the significant water-bearing units, determining any regional patterns of ground-water contamination, and analyzing the water chemistry of several major springs in the area.