Surface Water_Content Page_Water quality criteria

Water Quality Criteria

The Clean Water Act requires states to adopt water quality standards to protect aquatic life, wildlife and recreation. Water quality standards consist of three components: antidegradation, designated uses and water quality criteria. Water quality criteria represent the quality of water that supports a particular designated use.

Water quality criteria are either narrative or numeric

Narrative criteria are statements that describe the desired water quality goal.

Numeric criteria are benchmarks set at a level of a pollutant that is protective of the designated use.

Wisconsin's narrative criteria apply to Wisconsin's lakes, rivers and streams. These criteria address pollutants such as:

  • floating or submerged debris, oil, scum or other material;
  • substances that cause objectionable deposits on the shore or in the bed of a body of water;
  • substances that produce color, odor, taste or unsightliness;
  • substances in amounts which are toxic or harmful to humans; and
  • substances in amounts that are harmful to animal, plant or aquatic life.

Types of criteria for Wisconsin's lakes, rivers and streams

Wisconsin's numeric criteria are designed to protect a particular use for a given waterbody.

Types of criteria for Wisconsin's lakes, rivers and streams

Public health and welfare criteria

  • Toxics: Protect people from cancer or other effects caused by long-term exposure to eating contaminated fish or drinking contaminated water.
  • Temperature: Protect people from being scalded
  • Taste & odor: Limit objectionable tastes or odors of water and fish

Recreation criteria

  • Bacteria: Protect people from illness caused by exposure to bacteria from contamination by human waste
  • Phosphorus: Protect recreation by reducing the frequency of algal blooms

Wildlife criteria

  • Toxics: Protect fishing eating animals from effects caused by long-term exposure to eating contaminated fish and drinking contaminated water

Aquatic life criteria

  • Toxics: Protect aquatic organisms from adverse effects caused by short and long term exposure to contaminated water
  • pH: Protect aquatic organisms from changes in pH
  • Temperature: Protect aquatic organisms from effects caused by short- and long-term exposure to high temperatures.
  • Dissolved oxygen: Protect aquatic organisms from changes in dissolved oxygen concentrations
  • Phosphorous: Protect aquatic organisms from the effects of nutrients and algae on habitat

Links to criteria in Wis. Admin. Code

  • NR 102 contains criteria for phosphorus, dissolved oxygen, pH, bacteria and temperature. It also contains the narrative criteria described above.
  • NR 103 contains water quality standards for wetlands.
  • NR 104 contains a list of waterbodies designated as "limited" and certain water quality standards that apply to those waters (additional standards applying to “limited” waters are contained in NR 102 and 105).
  • NR 105 contains criteria for a wide variety of toxic substances.