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, but the overall trend is worsening marine water quality.
Water Quality in Freshwater Bodies Thurston County monitors water quality in specific bodies of water. Monitoring stations may change from year to year as resources/needs change. Sampling sites for streams and rivers are typically located near the stream mouth before it discharges into a larger body of water while sampling sites for lakes (not included in the chart above) are typically located in the deepest part of the lake.