Environmental Protection

Surface Water Quality Assessment Process

Subscribe to receive updates about water quality standards and assessments. The Clean Water Act (CWA) requires states to assess the quality of its surface waters and report the results to the public.

Surface Water Impairments and Pollutants

Impaired waters are identified by comparing monitoring results for a given water to water quality parameter thresholds, which provide guidelines for identifying water quality conditions. Impaired waters in Wisconsin are affected by a variety of…

Featured water restorations

Since 2002, Wisconsin has delisted 147 individual streams, lakes and beaches, representing approximately 500 stream miles and 52,800 lake acres. Below are a few stories of the road to these waters' aquatic health recovery.

Water Condition Lists

Every two years, Sections 303(d) and 305(b) of the Clean Water Act (CWA) require states to publish a list of all waters not meeting water quality standards and an overall report on surface water quality status of all waters in the state. To comply…

Clean Water Act Water Quality Plans and Reports

Water Condition Viewer

In order to keep DNR servers up to date, DNR will be patching the GIS servers to the latest service level on the morning of Sunday, March 30. During this update, users may see unexpected issues with DNR’s web map viewers. We apologize…

Surface Water Designated Uses

Assessing the health of a waterbody starts with determining what types of activities the water should support, also commonly referred to as a waterbody's Designated Uses. Under the Clean Water Act, Wisconsin waters are each assigned four uses that…

Surface Water Data Viewer

In order to keep DNR servers up to date, DNR will be patching the GIS servers to the latest service level on the morning of Sunday, March 30. During this update, users may see unexpected issues with DNR’s web map viewers. We apologize…

Water Quality Standards and Classifications

Water quality standards are important because they help water quality managers protect and restore the quality of Wisconsin's waters. Our water quality may be impacted by many different sources and types of pollution. Under the Clean Water Act,…

Watershed Restoration & Protection Viewer

In order to keep DNR servers up to date, DNR will be patching the GIS servers to the latest service level on the morning of Sunday, March 30. During this update, users may see unexpected issues with DNR’s web map viewers. We apologize…