Impaired waters are segments of streams, rivers, or lakes that do not meet the State of Washington’s Water Quality Standards for bacteria, dissolved oxygen, temperature, toxics, or other pollutants. This indicator reports on changes in the assessed category of water quality for waterbodies monitored under Section 303(d) of the Clean Water Act.
The fate of listings whose water quality condition was reported on in both the 2004 and 2014 Water Quality Assessment (a total of 2,071 listings).
Key Indicator Results
Since 1988, water quality has been assessed in approximately 10 percent of the waters of Washington State.
As of 2014, 1,694 listings (about 17 percent) are in Category 5, per the Candidate 303(d) list. 741 listings also do not meet water quality standards but are in Categories 4A and 4B because they have an established cleanup plan.
2,071 listings were reported on in both 2004 and 2014. Of these, the status of 68 listings changed category from impaired (Categories 5, 4A, or 4B) to non-impaired (Category 1). 392 listings moved from a non-impaired status to an impaired status between assessments.
The fate of the majority of listings (852) was unchanged and remained impaired, while an additional 759 listings remained non-impaired.
Reduce the number of “impaired” waters.
Washington State Department of Ecology, 303(d) List