Amendments to Water Quality Standards: Use classifications 3 and 4

In this rulemaking, the MPCA proposes to amend the existing rules governing water quality standards for industrial consumption (Class 3) and agricultural (Class 4A) and livestock and wildlife usage (Class 4B). Please note that this rulemaking will not address the Class 4A wild rice sulfate standard.

Making changes to Class 3 and 4 standards will protect state waters while lowering regulatory hurdles

Minnesota has many standards to protect water quality for drinking, swimming, fishing, boating, and more. Water quality standards are set to protect “beneficial uses” — drinking water, aquatic life, aquatic consumption (ability to safely eat fish), aquatic recreation, etc. The standards all work together to ensure we all benefit from our lakes, rivers, and groundwater. The MPCA is proposing amendments to its Class 3 and 4 water quality standards. Class 3 standards govern water quality for industrial use and Class 4 standards govern agricultural and wildlife usage. More than 150 municipal wastewater treatment plants and some industrial plants that discharge treated wastewater are impacted by the current standard.

The current standards contain narrative statements of what the quality of the waters should be and numeric thresholds for a variety of pollutants.

  • Class 3: chloride, hardness, pH
  • Class 4A (irrigation): bicarbonate, boron, pH, specific conductance, total dissolved salts, sodium, radioactive materials
  • Class 4B (livestock and wildlife drinking): pH, total salinity

Many organizations and individuals have submitted comments to the MPCA on revising these standards. Some favor revisions, while others fear that changes will worsen Minnesota’s water quality and harm drinking water, recreational uses, or aquatic life and plants. In the proposed rules, the agency lays out a robust implementation process to ensure water quality is protected.  

Proposed changes

Applying modern science to the standards will provide a more nuanced, localized approach to protecting water quality. In addition, the revised standards will allow for flexibility in creating permits, reduce wastewater permitting delays, and avoid wastewater treatment costs that don’t provide environmental benefits. The amended standards are the result of years of engagement and input from community partners across the state. MPCA received thousands of comments expressing concerns of the amended standards’ impact on agriculture, industry, and wildlife.

The MPCA is proposing several changes within each use classification:

  • Class 3. The MPCA is proposing to consolidate the three subclasses into one standard. In addition, the numeric standards will be removed while the narrative standard will be retained and updated. Finally, the amended standards will provide clarity around implementation of the narrative standards in discharge permits, including a robust implementation approach that is based on specific site conditions and focuses on water hardness.
  • Class 4. For Class 4A (irrigation), many of the numeric standards will be removed while the narrative standard will be retained and updated. The amended standards will provide clarity around implementation of the narrative standards in discharge permits, including a robust implementation approach that is based on specific site conditions and focuses on water hardness. For Class 4B (livestock and wildlife drinking), the salinity standard is revised based on current science and common water quality indicators. In addition, there is a sulfate and nitrate standard that will protect livestock and wildlife.

Draft rules: PDF icon Draft rule language (wq-rule4-17j)

The proposed Class 3 and Class 4A revisions rely on narrative water quality standards — statements about the types of adverse impacts from poor water quality that must be avoided. Narrative water quality standards require an additional step or “translation” in order to be used in other water quality programs. The MPCA is proposing detailed methods to determine if permitted facilities need limits on the level of pollutants in their discharge in order to make sure they do not cause or contribute to the kind of poor water quality that the standards are designed to prevent.

Rulemaking schedule and process

Over the past few years, MPCA has gathered input and feedback on the proposed amendments to class 3 and 4 standards. The amended standards are the result of months of engagement and input from community partners across the state. MPCA received thousands of comments expressing concerns about the impact of amended standards on agriculture, industry and wildlife.

Late October 2020

To give the public more time to review the proposed rule language, the MPCA will post its draft rule on the agency’s website by October 30. The agency will not be soliciting comments on the draft until the formal notice period. The MPCA previously asked for public feedback during two comment periods in 2016 and 2019.

December 2020

The proposed rule language, along with Statement of Need and Reasonableness (SONAR), were published with a notice of intent to adopt the rule. The notice included a schedule for an administrative law judge hearing. The public may provide comments prior to the hearing through the rulemaking e-comments site at the Office of Administrative Hearings.

February 4, 2021

The Office of Administrative Hearings conducted an administrative law judge hearing. See resources posted in the Rulemaking and technical support documents section.

The public has an opportunity to provide comments during the post-hearing comment period that runs through 4:30 p.m. on Feb. 24, 2021.

Other points

March – August 2021

The Office of Administrative Hearings (OAH) report regarding the proposed rule changes is due 30 days after the close of the post-hearing comment period; it will be posted on the OAH web site. The report may lead to needed changes to the rule. If the rule is approved, MPCA will go through the process to formally adopt the rule and submit it to U.S. EPA for approval.

Rulemaking and technical support documents

March 3, 2021

Feb. 24, 2021

Feb. 17, 2021

Feb. 4, 2021

PDF icon Public hearing transcript (Feb. 4. 2021) (wq-rule4-17q)

This is the official hearing record from the Feb. 4, 2021, public hearing.

Recording of the public hearing (6 hours)

Dec. 28, 2020

Dec. 14, 2020

Submit written comments to the administrative law judge via the Office of Administrative Hearings Rulemaking eComments website.

2020 Preliminary draft rule language

Comments will not be taken until the rule language and SONAR are made available as part of a formal Notice of Intent to Adopt Rules with a Hearing.

2019 Request for comments (March 11 - April 22, 2019)

2016 Request for comments (Feb. 8 – April 8, 2016)

2010 Evaluation from the University of Minnesota’s Department of Bioproducts and Biosystems Engineering

Contact information

For technical questions about these use classifications and the proposed changes:
Scott Kyser: scott.kyser@state.mn.us, 651-757-2665

For questions about rulemaking:
Yolanda Letnes: yolanda.letnes@state.mn.us