Water Quality > Assessment/TMDLs

Water Quality Assessment (303[d]) & Water Quality Improvement Projects (TMDLs)

Water Quality Assessment (303[d])

Washington State's Water Quality Assessment lists the water quality status  for a particular location in one of 5 categories recommended by EPA. This Assessment represents the Integrated Report for Sections 303(d) and 305(b) of the Clean Water Act.

General 303(d) List Information | Proposed 2008 List | 2004 List | more

Water Quality Improvement Projects (TMDLs)

Water Quality Improvement Projects, or TMDLs (Total Maximum Daily Loads) are the amounts of pollutant loading that a given water body (river, marine water, wetland, stream, or lake) can receive and still meet water quality standards. TMDLs are implemented through Waste Load Allocations, inserted as pollutant limits in permits to point source dischargers, and through Load Allocations and non-regulatory programs for nonpoint sources.

TMDLs Home Page | TMDLs in Your Watershed

Data Quality Assurance

Information on water quality data assurance - what it is, why it is important, and what the State of Washington is doing to support quality assurance of water quality data.

General Data Quality Information | Data Quality Policies