Skip to main content

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, every state must adopt water quality standards to protect, maintain and improve the quality of our nation’s surface waters. These standards set the appropriate level of protection by:

Water quality standards also support efforts to achieve and maintain protective water quality conditions, including:

Public participation

Any interested individual can have a role in the process of developing water quality standards. The DNR reviews and, as appropriate, revises water quality standards at least once every three years. To find out more about this process and how you can be involved, visit triennial standards review.

When revisions to water quality standards are proposed, the public is notified of these revisions and a public hearing is held to gather input and comments. Several water quality standards rules are currently under revision or development. For a brief description of these revisions, visit water quality standards updates.

Areas of Special Natural Resources Interest (ASNRI)

The state also classifies waterbodies using several categories that indicate special ecological value, which collectively are known as Areas of Special Natural Resources Interest (ASNRI).  While ASNRI classifications are not explicitly water quality standards like designated use classifications, they are an important basis for many types of management decisions.

ASNRI-designated areas include the following: