Amendments to Water Quality Standards — Use Classifications 3 and 4

The Clean Water Act requires a regular review of state water quality standards, and one important aspect of that review is the updating of designated use classifications. In this rulemaking, the MPCA proposes to amend the existing rules governing water quality standards for industrial consumption (Class 3) and agricultural and wildlife usage (Class 4). Please note that this rulemaking will not address the Class 4A wild rice sulfate standard, which is the subject of a separate rulemaking effort.

Planned changes to the Class 3 use include replacing numeric standards for the existing subclasses (3A–3D) with a single narrative standard. This standard would apply only to surface waters subject to the Minnesota Department of Natural Resources (MDNR) water appropriations permitting program for specific industrial uses. The Class 3 use class would no longer apply to all surface waters of the state.

Planned changes to Class 4A (Agricultural Use and Irrigation) and Class 4B (Wildlife and Livestock Watering) include updating numeric standards to reflect current science, and retiring the applicability of the Class 4A standards. Class 4B standards would continue to apply to all surface waters of the state. The MPCA will also consider any other rule changes needed in order to implement the desired changes to the Class 3 and Class 4 standards.

A 2010 evaluation of this topic from the University of Minnesota’s Department of Bioproducts and Biosystems Engineering is available:

Rulemaking documents

Not yet available.

You can register at GovDelivery to be notified when draft rule language is published.

The public comment period on this rulemaking’s Request for Comments closed on April 8, 2016.

Register at GovDelivery to receive notice of upcoming Use Class 3 and 4 rulemaking activities.

Stages of rulemaking

Request for comments Published February 8, 2016; comment period ended April 8, 2016
Drafting of rule language/SONAR  
Pre-proposal public engagement period  
Public comment period/Notice of hearing  
Post–comment period/Administrative Law Judge review  
Adoption of rules  
U.S. Environmental Protection Agency review and approval  

Contact information

For questions about the status of the rulemaking or how to submit comments:
Katie Izzo:, 651-757-2595

For technical questions about these use classifications and the proposed changes:
Gerald Blaha:, 651-757-2234