What are unclassified waters and why are they important?

More than forty years after passage of the Clean Water Act, Missouri ’s unclassified waters are not even receiving the minimal protections required by the Act.  Missouri ’s creeks and streams are critical parts of our large river systems. As feeder streams for our big rivers, they serve as nurseries for young fish, habitats for wildlife, and form an intricate network of flowing water to our major riverways. When these unclassified rivers, streams, lakes, and wetlands are not healthy, our bigger rivers are impacted.



Before 2014, more than 85% of Missouri ’s streams had never been classified, meaning nearly 150,000 miles of streams received inadequate protection from water pollution under Missouri ’s water quality laws. Unclassified streams were generally smaller than Missouri ’s larger, classified water bodies, but their protection is equally important given the disproportionate number of pollutant discharges into these waters. Many lakes and almost all wetlands in Missouri lack classifications as well. In 2014, Missouri adopted the 1:100K rule, referring to the scale of once inch on the USGS map to 100,000 real inches, as the basis for classifying waters of the state.  Uses and water quality protections now apply to those streams which are visible on the 1:100,000 map. While we gained ground in water protections, at least 65,000 stream miles; 90,000 acres of lakes and reservoirs; and almost 1,000,000 acres of wetlands remain unprotected.


All waters we want protected                                               Classified waters from 2004-2014

WOTUS Composite

What is MCE doing about unclassified waters?

The classification of a water body is the first step in the Clean Water Act that gives it needed protection from pollution. Classified waters are assigned a designated use and corresponding water quality standards that set the pollution limits necessary to meet the specified use. Under the U.S. Clean Water Act, all waters of the United States have a default designated use of fishable/swimmable—meaning all waters should be clean enough for life to survive in them and for humans to safely come in contact with the water.

The Coalition would ultimately like to see all of Missouri’s waters classified. We are working to push Missouri’s DNR Water Protection Program and the EPA to provide adequate protections for all waters of the state, making them safe for human recreation and aquatic life. The state and the EPA must step up and protect all our waters under the Clean Water Act. MCE supports the Clean Water Protection Rule because although Missouri only applies Water Quality Standards to the waters on the 100K map, we hope it is a step towards getting protections on more waters.