The quality of surface and groundwater influences the quality of life in Thurston County.
Water Quality in Puget Sound
The Marine Water Condition Index (MWCI) displays changes in the water quality of Puget Sound. Numbers greater than zero show water quality that has improved over the baseline and numbers smaller than zero indicate decreased water quality. Two areas in or near Thurston County are tracked as part of the MWCI: South Sound, a combination of the Nisqually Reach and Dana Passage measuring stations; and Budd Inlet. These stations have exhibited wide changes from year to year, though both have seen gradually improving water quality.
Groundwater provides water for the majority of residences and commercial industries in Thurston County. More than 1,200 public water supplies and over 8,000 private wells use groundwater in the county, and these sources account for approximately 99 percent of the drinking water for County residents. Information about the quality of groundwater, and drinking water resources in incorporated communities can typically be found in an Annual Water Quality Report produced by each jurisdiction (and required by the Department of Ecology). Due to the variability in these reports, TRPC does not track the groundwater data.