As recently as 20 years ago, the Basin experienced serious water pollution and public health problems from the discharge of untreated sewage and wastes. Since then, water quality has improved as a result of required industrial waste treatment, and a large investment of state, federal, municipal and private funds for sewage treatment facilities.

However, additional clean-up must also address nonpoint source runoff from urban and agricultural areas. Nonpoint source runoff can include pollutants such as nutrients, low levels of persistent toxic substances, and pathogens.

• Phosphorus Pollution
• Stormwater Runoff
• TMDLs (Total Maximum Daily Load)
• Toxic Substances

For information about blue-green algae, swimming, drinking water, and fish advisories, visit the Human Health pages.

The Data and Monitoring pages contain information about water quality monitoring programs and links to lake and watershed data sources.