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

This page refers to 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.

To find water quality standards that apply to the Columbia River basin, visit:

For more information about water quality standards, visit Water quality standards: regulations and resources.

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.

To find EPA-issued NPDES permits in the Columbia River basin, visit:

Learn more about EPA's NPDES program.

Total Maximum Daily Loads (TMDL)

A total maximum daily load (or TMDL) is a type of water quality "cleanup plan" for rivers, streams, lakes, and 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.

To find TMDLs for waterbodies in the Columbia River basin, visit:

TMDL for temperature in the Columbia and Lower Snake Rivers
TMDL for mercury in the Willamette Basin
Visit How's My Waterway to search for other TMDLs.

For more information about TMDLs in Region 10 (including Idaho, Oregon, and Washington), visit Impaired waters and TMDLs in Region 10.