MPCA revises schedule for new Class 3 and 4 water quality standards

(updated December 15, 2020)

The Minnesota Pollution Control Agency (MPCA) has released a revised schedule for proposed amendments to water quality standards for industrial consumption (Class 3) and agricultural and wildlife usage (Class 4). The agency posted its draft rule on October 28. The Statement of Need and Reasonableness (SONAR) and rulemaking procedures was issued on December 14, and the public comment period is open through February 4, 2021. Following the public participation process, the MPCA anticipates the formal adoption of the revised rules in 2021.

These revised water quality standards will affect facilities that discharge wastewater containing dissolved salts to Class 3 or 4 waters. Dissolved salts are regulated as TDS, chlorides, hardness, sulfates, bicarbonates, salinity, and specific conductance. Barr has been closely tracking these amendments for 10 years and is working with facilities to assess possible impacts. To learn more about these proposed rule revisions, contact Nick Nelson at 952-832-2701 or


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