The Minnesota Pollution Control Agency (MPCA) has released the 2020 Impaired Waters list, which could have a significant impact on many municipal wastewater treatment facilities.

A water body is considered “impaired” if it fails to meet one or more of the state’s water quality standards. The MPCA is required to update the impaired waters list every two years under the Federal Clean Water Act. If a water body is designated as impaired, MPCA is required to complete a Total Maximum Daily Load (TMDL) study for that water body or segment, and a new impairment listing may result in more restrictive effluent limits for your facility in the future. This, in turn, could require expensive upgrades.

This year, 528 new water bodies and 728 impairments were added to the list. We urge each community to review the list to determine if there are any new impairments for any water bodies downstream of your facility’s discharge. Be sure that this information makes it to your wastewater staff and/or consulting engineers to make that review. If your wastewater team identifies any proposed impaired waters downstream of your discharge it is critical to evaluate those impairments to determine the potential impact for your facility. 

If a proposed impairment will impact your facility, your wastewater team should request the background data to confirm that MPCA’s decision is accurate. If your team believes the impairment decision is inaccurate, you should provide comments to MPCA.

MPCA occasionally makes mistakes in its impairment designations and it can be a difficult and lengthy process to correct them after the fact. You may reach out to MPCA staff with questions or data requests by contacting Miranda Nichols. The deadline for comments is Tuesday, Jan. 14.