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Columbia River

Water Quality Standards, Permits, and Plans (TMDLs) in the Columbia Basin

This page summarizes several key technical resources that regulators and scientists use to help protect water quality in the Columbia River and its tributaries.

Water Quality Standards

Water quality standards are science-based requirements developed by states and tribes to protect rivers, lakes, streams, and wetlands based on the use and value of the waterbody for:

  • public water supply
  • protection of fish, shellfish, and wildlife
  • recreational, agricultural, industrial, and navigational purposes.

Since the Columbia River basin covers parts of many states and tribal lands, different water quality standards may apply to different parts of the river and its tributaries. Refer to the links below to find more information about water quality standards that apply to the Columbia River basin.

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Wastewater and Stormwater Permits

EPA, states, and authorized tribes issue "end of pipe" permits under the National Pollutant Discharge Elimination System (NPDES) to facilities that discharge wastewater or stormwater directly to rivers, lakes, streams or other surface water.

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Total Maximum Daily Loads (water quality cleanup plans)

A total maximum daily load (TMDL) is a type of water quality "cleanup plan" for rivers, streams, lakes, or other bodies of water. It identifies the amount of a specific pollutant (such as fecal coliform, phosphorus, or temperature) that a water body can receive and still meet water quality standards. TMDLs are typically issued by the state's environmental agency and approved by EPA.

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