Water Quality Standards

Designated Uses and Criteria

States classify water bodies based on how the river, lake, or stream is primarily used. These designated uses can include drinking water, recreation, and habitat for aquatic life.

States then set water quality criteria, which describe the conditions a water body must meet to support its designated use. Guided by the EPA, states have developed criteria for a wide variety of pollutants and problems, including bacteria and nutrients.

View from a bridge

To protect healthy water quality, states set anti-degradation policies to make sure that water bodies can continue to support their designated uses.

Together, the designated uses, water quality criteria, and anti-degradation policies make up a state’s water quality standards.

Appropriate water quality standards are a core component of the Clean Water Act (CWA). They underpin many other CWA programs, including water quality monitoring, total maximum daily loads (TMDLs), National Pollutant Discharge Elimination System (NPDES) permits, nonpoint source programs, oceans and wetland programs, and source water protection.

Water Quality Monitoring

An integral part of the Clean Water Act equation, monitoring can be used to assess the types and sources of pollution loading into a watershed, to determine the progress of current water quality programs, and to document the health of watersheds. Section 305(b) of the Clean Water Act requires all states to provide a report on the status of their water bodies on a biennial basis. The ten elements in a statewide monitoring program that are required in the Comprehensive Monitoring Strategy are as follows:

  • A monitoring program strategy
  • Monitoring objectives
  • A monitoring design
  • Core and supplemental water quality indicators
  • Quality assurance
  • Data management
  • Data analysis and assessment
  • A reporting scheme
  • A programmatic evaluation
  • General support and infrastructure planning

The U.S. EPA hosts a workgroup that meets annually to discuss relevant policy, funding and scientific issues related to water quality monitoring.

A group of people talk at a water quality standards meeting

Water Quality Standards Workgroup

NEIWPCC has a Water Quality Standards Workgroup made up of our state and federal partners. This group meets twice a year, or as needed. The goal of the workgroup is to identify interstate water quality issues, not to seek uniformity in the states’ standards and classifications.

The group provides a forum to improve interstate communication to develop solutions and identify potential issues before they arise. To do this, the workgroup has developed interstate matrices, to summarize our member states’ water quality standards and waterbody designated uses and classifications. We have also established a northeast-specific Water Quality Standards Training to bring together state staff from around the region to learn and share information about state standards.

The NEIWPCC staff closely follows any developments and changes to our states’ water quality standards and related litigation. As new water chemistry and toxicity studies are released, the states and EPA each compile and analyze relevant evidence for a particular toxin or parameter to determine if updates to criteria are necessary. All state water quality standards must be reviewed every three years and formally submitted and maintained in EPA’s Water Quality Docket.

In addition to developing specific criteria guidance and standards, states must also respond to new and revised regulations and rules proposed by EPA. Some recent rulemaking highlights include EPA proposals to clarify water quality standards regulation, to help states determine which streams and wetlands are protected by the CWA, and to update bacteria criteria for protection of human health in recreational waters.

NEIWPCC works with the Water Quality Standards Workgroup to help states provide a unified regional response to proposed rules through comment letters, and then facilitates discussions on how states can best approach implementation once the rules are finalized.

For more information on water quality standards and our workgroup, contact Emma Gildesgame, the coordinator of our Water Quality Standards Workgroup.