The Montana Department of Environmental Quality (DEQ) decides what water bodies are impaired and with what pollutants. If a stream is labeled impaired, it means that the stream does not meet Montana water quality standards. The stream has levels of a pollutant that are higher than what is healthy for either aquatic life, recreational activities, or drinking water.
In Kalispell, we have 4 steams and rivers that are listed as impaired or unhealthy by Montana DEQ.