Last week, the Minnesota Pollution Control Agency released the 2020 Impaired Waters list. This is an important regulatory event that could have a significant impact on your wastewater treatment facility. 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 state’s impaired waters list every two years under the Federal Clean Water Act. If a waterbody is designated as impaired MPCA is required to complete a Total Maximum Daily Load (TMDL) study for that impaired waterbody or segment, and a new impairment listing may result in more restrictive effluent limits for your facility in the future.

Review the impaired waters list and submit comments

We urge all MESERB members to go through the list and materials on MPCA’s website to determine if there are any new impairments for any of the waterbodies/waterbody segments downstream of your facility’s discharge. You can search new impairments by selecting the “2020 Inventory Impaired Waters” tab on the spreadsheet (which can be downloaded from the link above) and selecting the year 2020 in column D of the spreadsheet entitled “Year added to List.” You can also view proposed impairments via MPCA’s Interactive Map (Impaired Waters Viewer).

If you identify any proposed impaired waters downstream of your discharge it is critical for you to evaluate those impairments to determine the potential impact for your facility. If you believe a proposed impairment will impact your facility, you should request the background data to confirm that MPCA’s impairment decision is accurate. If you believe the impairment decision is not accurate, you should provide comments to MPCA.

We strongly advise you to work with your consultant or expert staff to review these materials carefully and submit comments to MPCA if warranted. 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 if questions or data requests by contacting Miranda Nichols. Nichols and her team are very helpful and generally respond quickly to requests for information.

The deadline to submit comments is Tuesday, Jan. 14, 2020 by 4:30 p.m. Submit written comments to or Miranda Nichols, Minnesota Pollution Control Agency, 520 Lafayette Rd N, St. Paul, MN 55155 (must provide a return address).

MESERB will be looking through the list and will determine if we need to submit general comments on behalf of our organization as a whole. MESERB does not have the resources to review the proposed impairments that impact each individual member and provide comments. However, if you have questions about how to review the data and how to submit comments, please contact Gretel Lee at or Daniel Marx at and we are happy to assist you.