Iowa DNR 305(b) Water Quality Assessment Database

ADBNet is an online database tracking Iowa's water quality assessments. These assessments are prepared under guidance provided by the US EPA under Section 305b of the Clean Water Act to:

  • estimate the extent to which Iowa's waterbodies meet the goals of the Clean Water Act and attain state water quality standards, and
  • share this information with planners, citizens and other partners in basin planning and watershed management activities.

Water quality in Iowa is measured by comparisons of recent monitoring data to the Iowa Water Quality Standards. Results of recent water quality monitoring, special water quality studies, and other assessments of the quality of Iowa's waters are used to determine the degree to which Iowa's rivers, streams, lakes, and wetlands support the beneficial uses for which they are designated in the Iowa Water Quality Standards (for example, aquatic life (fishing), swimming, and/or use as a source of a public water supply). Other information from water quality monitoring and studies that are up to five years old are also used to expand the coverage of assessments in the report. Waters assessed as impaired (that is, either partially supporting or not supporting their designated uses) form the basis for the state's list of impaired waters as required by Section 303(d) of the Clean Water Act.

Summaries of Section 305(b) assessments for all states are available from U.S. EPA.