Water Quality

Standards
States and authorized Tribes adopt water quality standards for each waterbody within their borders. EPA is responsible for reviewing new or revised water quality standards to ensure they meet the requirements of the Clean Water Act and that they will not interfere with the attainment of standards in other States. Additionally, EPA provides technical guidance and assistance to States and Tribes to help implement the water quality standards program.

Monitoring
Water Quality monitoring is conducted by the States, Tribes, EPA staff, other federal agencies, and other organizations such as volunteer monitoring groups. Monitoring is conducted for a variety of reasons, including to characterize waters and identify changes or trends in water quality over time; identify specific existing or emerging water quality problems; gather information to design specific pollution prevention or remediation programs; determine whether program goals -- such as compliance with pollution regulations or implementation of effective pollution control actions -- are being met; and respond to emergencies, such as spills and floods.

Assessments and Reporting
Data collected from our monitoring programs are used to develop assessments of water quality that provide useful information for protecting and restoring our water resources. Assessments are often made against the water quality standards adopted by States and Tribes.
Clean Water Act Section 305(b) Reporting in Region 5 - The Clean Water Act requires each state to conduct water-quality surveys and report the findings to EPA every two years. These reports provide the basis for the National Water Quality Inventory: Report to Congress. Summaries of each State report are also developed by EPA.

State water quality websites with links to state documents -
- Illinois
- Indiana
- Michigan
- Minnesota
- Ohio
- ORSANCO
- Wisconsin