MPCA’s water quality standards work plan, 2018 - 2020

The MPCA’s work plan for 2018 to 2020 includes projects currently in the rulemaking process and others that are in development and not yet ready for rulemaking.  See the written description of the work plan for more detail about each project and expected development timelines.

Water quality standards work plan for 2018 to 2020

PDF icon Water quality standards work plan, 2018 - 2020 (PDF)

Water quality standards work plan for 2018 to 2020

Group 1A projects

Group 1A projects have an estimated timeline for adoption into state law. In this stage, the MPCA is responding to changes needed due to peer review (where applicable), finalizing the technical support document, and developing the Statement of Need and Reasonableness and final rule language. The need for peer review will affect the rulemaking timeline.

Use Classes 3 (industrial) and 4 (agriculture and wildlife)

Revision of the water quality standards and approach for protecting Class 3 (industrial) and Class 4 (agriculture and wildlife) use classes, which are as follows:

  • Class 3 water quality standards protect waters for general industrial purposes, industrial cooling, and materials transport.
  • Class 4A water quality standards protect source waters used for irrigation purposes.
  • Class 4B water quality standards protect waters used for livestock and by wildlife.    

Finalization of the technical approach for revising use class designations and associated water quality standards continues. MPCA anticipates the draft technical support document will be out for public comment in 2018, and may go through peer review. Learn more.

Group 1B projects

In Group 1B projects, the agency is preparing supporting documentation and has a basic concept of what may be included in the rule language. Draft technical support documents for new or revised numeric standards go through an initial public comment period and independent peer review process. When the document is complete enough for formal peer review or public review, generally in two to three years, the pre-rulemaking (Group 1B) projects will move into formal rulemaking.  

Use Class 1 (domestic consumption)

The proposed Class 1 revisions will better define and protect waters used for domestic consumption (drinking water use and food processing), and address the inconsistencies and gaps in Minn. R. chs. 7050 (waters of the state) and 7060 (underground waters). Revisions under discussion by MPCA, the Minnesota Department of Health, and other state agency partners include the following: 

  • Clarifying that waters used for domestic consumption should undergo treatment authorized by MDH. 
  • Adding language to protect surface waters used for domestic consumption by making health risk limits equivalent to Class 1 water quality standards.
  • Adding language to address surface water and groundwater interaction.
  • Adding the concept of groundwater contaminant management zones to inform the public, state and local regulators, and others about areas of groundwater contamination.

Development of the revisions continues. More information on likely rule changes and supporting rationale will be available as progress is made, probably in 2018.

Surface water pathogens (Escherichia coli or E. coli) – Recreational and human health

MPCA is revising the recreational water quality standards for human health protection from surface water pathogens (E. coli) for Class 2 and Class 7 waters. E. coli is a bacterium that is present in human digestive tracts and is used as an indicator of the presence of potentially harmful bacteria, viruses, and other microbiological pathogens in lakes and rivers. The revision will update Minnesota’s standards for pathogens to be consistent with the EPA’s 2012 recreational water quality criteria. The revision is not planned to affect the bacteria indicator used by wastewater permits. The MPCA anticipates that draft rule documents will be available in 2018. Learn more.

Use Classes 2A (cold waters) and 2B (cool and warm waters) 

The MPCA is using new biological criteria such as indices of biotic integrity to assess water conditions, and must revise the Class 2A and 2B designations to align with these improved tools. In making the revisions, the MPCA will consult the Minnesota Department of Natural Resources’ recently updated list of trout waters in Minn. R. 6264.0050, which further informs the revisions. 

Group 2A projects

Group 2A projects have all the information needed from outside the MPCA to evaluate how the standard will address environmental or programmatic concerns, and to assess the resources needed to promulgate and implement the standard. To move the project into Group 1, the agency must determine if it's able to accommodate the standard-development work in addition to its regular permitting and related work. Group 2A projects are likely to move into Group 1B within one to two years.

No projects are in Group 2A at this time.

Group 2B projects

Group 2B projects are in initial technical development, which may involve reviewing scientific literature or Minnesota-specific data, designing and undertaking studies, or reviewing and refining an EPA criteria document. Group 2B projects need additional information to complete technical development and move to Group 2A; such information may not be available for months or years.


Nitrate in lakes, rivers, and streams can contribute to the increased growth of aquatic plants and nuisance algal blooms, and can be toxic to aquatic organisms. The major source of elevated nitrate in surface waters is cropland, although municipal and domestic wastewaters also contribute. Development of a Class 2 aquatic life water quality standard for nitrate is a long-time priority of the MPCA. The agency developed a draft technical support document for nitrate in 2010 [PDF icon Aquatic Life Water Quality Standards Technical Support Document for Nitrate (wq-s6-13)], but put further development on hold when the EPA funded supplemental nitrate aquatic-life toxicity tests. Final study results are still pending. The MPCA doesn't anticipate the nitrate standard will move into Group 1 in the next three years. See the agency's Report on nitrogen in surface water for more information.

Ammonia - aquatic life

The Class 2 aquatic life standard for ammonia was selected for revision in the last triennial standards review. Ammonia is a common wastewater pollutant that is toxic to aquatic life; ammonia can also be discharged to the environment in runoff from cultivated lands and animal agriculture facilities. The EPA issued a revised criteria for ammonia in 2013. Because ammonia and nitrate are related nitrogen-based pollutants, MPCA plans to revise the ammonia water quality standard when it begins development of a nitrate standard. 

Chloride – aquatic life

Chloride from road salt (via urban runoff) and water softener salt (via wastewater discharges) is harmful to aquatic life in surface waters. The Class 2 aquatic life standard for chloride was selected for revision in previous triennial standard reviews because new information suggested Minnesota’s standard was based on potentially outdated science. Scientific studies have demonstrated that the interactions of ions (e.g., chloride, sulfate, calcium, and others) must be considered to accurately account for chloride’s toxicity. Studies that support development of the chloride standard are not finalized. 

Sulfate – aquatic life

Sulfate from municipal and industrial wastewater discharges, including mining, can degrade water quality. Adding a Class 2 aquatic life standard for sulfate was selected in the last triennial standard review. Recent scientific studies show that the interactions of ions affect sulfate's toxicity. Study of sulfate’s impact on aquatic life, individually and in combination with other ions, has been underway for several years, and final study results are still outstanding.

Group 3 projects

The MPCA has not started developing Group 3 projects, because of missing technical information, a lack of capacity, or both. Group 3 projects represent areas where the MPCA believes standard development is likely, but these projects may remain in Group 3 without significant progress into regulatory development throughout the three year triennial period.

Human health water quality standard for PFOS in fish tissue

Minnesota needs a fish-tissue based human-health water quality standard for perfluorooctanesulfonic acid (PFOS) to address the large number of state waters with PFOS-contaminated fish. PFOS is an industrial pollutant that is bioaccumulative; Minnesota has been monitoring the presence of PFOS in fish tissue for several years. While MPCA does not anticipate having capacity to develop the human-health standard for PFOS in fish tissue during the next three years, the agency will likely update site-specific criteria for PFOS to address program needs at remediation sites and for watershed restoration and protection plans.

Group 4 projects

Group 4 projects do not have a priority status with regard to development but are important water quality standards work. They include review of outstanding resource value waters and review of Class 7 waters, both of which are conducted on an as-needed basis, such as when new information becomes available about a water body. A conceptual model for integrating review of listed Class 7 waters into the MPCA’s watershed approach is in very early development.