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