This page provides technical information intended for regulators and scientists 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.

• Idaho water quality standards Exit
• Oregon water quality standards Exit
• Washington water quality standards Exit
• EPA-approved tribal water quality standards
• Learn more about water quality standards

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.

• Find NPDES permits for facilities in Idaho, Oregon, and Washington
• Learn more about EPA's NPDES program

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.

• Search for TMDL documents related to the Columbia River and its tributaries.
• Learn more about EPA's TMDL program