Water Quality

Desired Trend


Current Trend

Baseline (2012): 709.5
Current (2015): 711.9

Theme Green


Rivers and streams impaired (polluted), in miles

Why is it Important?

Clean water is necessary for wildlife, agriculture, drinking water, and recreation. The Clean Water Act of 1972 requires states to monitor and report waters that do not meet water quality standards. The standards vary based on the designated use for the water, such as swimming, consumption, or navigation. Impaired waters are those that are polluted by one or more pollutants that threaten the designated use of the water.

How are we Doing?

As of 2015, 711.9 streams and rivers in the St. Louis region are impaired (polluted) and 4,092.3 acres of lakes are impaired.1 The amount of impaired rivers, streams, and lakes did not change significantly from 2012 to 2015.  

Geographic Level

St. Louis eight-county bi-state region, including Franklin, Jefferson, St. Charles, and St. Louis counties and the city of St. Louis in Missouri and Madison, Monroe, and St. Clair counties in Illinois. View map.


1This measure previously was defined as “Percent of assessed streams and rivers that are impaired.” The U.S. Environmental Protection Agency changed the number of streams and rivers assessed and therefore the OneSTL Performance Measure definition was revised. 

Data Sources

U.S. Environmental Protection Agency