Current Assessment Methodology Documents

Methodology for Iowa’s 2024 Water Quality Assessment, Listing, and Reporting Pursuant to Sections 305(b) and 303(d) of the Federal Clean Water Act

Previous Assessment Methodology Documents

• Methodology for Iowa’s 2022 Water Quality Assessment, Listing, and Reporting Pursuant to Sections 305(b) and 303(d) of the Federal Clean Water Act
• Methodology for Iowa’s 2020 Water Quality Assessment, Listing, and Reporting Pursuant to Sections 305(b) and 303(d) of the Federal Clean Water Act
• Methodology for Iowa’s 2018 Water Quality Assessment, Listing, and Reporting Pursuant to Sections 305(b) and 303(d) of the Federal Clean Water Act
• Methodology for Iowa’s 2016 Water Quality Assessment, Listing, and Reporting Pursuant to Sections 305(b) and 303(d) of the Federal Clean Water Act

GIS Datasets

• Impaired Waters
• Iowa DNR Geospatial REST services- water quality

Other Documentation

• Surface Water Classification - 2019
  • List of Iowa surface waters and their use designations.
• Iowa DNR - Impaired Waters
  • Links to downloads of previous Integrated Report documentation
• Iowa Administrative Code Chapter 61 - Water Quality Standards
• Iowa's Credible Data Law