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Water: Water Quality Standards

What are Water Quality Standards?

[Why are WQS Important?] [WQS Review and Revision] [Role of the Public] [Designated Uses] [Water Quality Criteria] [Antidegradation] [General Policies] [Indian Tribe Participation] [WQS Program History]

Basic Information

Water quality standards are the foundation of the water quality-based control program mandated by the Clean Water Act. Water Quality Standards define the goals for a waterbody by designating its uses, setting criteria to protect those uses, and establishing provisions to protect water quality from pollutants. A water quality standard consists of four basic elements:

  1. designated uses of the water body (e.g., recreation, water supply, aquatic life, agriculture),
  2. water quality criteria to protect designated uses (numeric pollutant concentrations and narrative requirements),
  3. an antidegradation policy to maintain and protect existing uses and high quality waters, and
  4. general policies addressing implementation issues (e.g., low flows, variances, mixing zones).

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