Minnesota's Water Quality: How Much Is Polluted?

Minnesota is known as the 'land of 10,000 lakes', but about 40% of its waters fail to meet basic health standards, according to state water quality reports. The Mississippi River and its tributaries are cleaner today than they were 30 years ago, but many challenges remain. Excess sediment, fertilizer from farm runoff, bacteria, and excessive river flows are among the issues affecting the state's waterways. The Minnesota River, for example, is deemed unhealthy due to a combination of pollutants and changes in river flows brought on by human activities. With 70% of nitrate pollution in Minnesota's waters originating from cropland, the agricultural industry has a key role to play in improving water quality.

Minnesota's water pollution sources

Minnesota is home to 11,800 lakes, 69,000 miles of rivers and streams, and 10.6 million acres of wetlands. However, about 40% of these waters fail to meet basic health standards, according to state water quality reports. In 2022, 305 water bodies and 417 impairments were added to the state's Impaired Waters List, bringing the total to 2,904 water bodies with 6,168 impairments.

One of the main sources of water pollution in Minnesota is agriculture. Excess soil, nutrients, and bacteria from farm fields can harm fish and other aquatic life. More than 70% of nitrate pollution in Minnesota waters comes from cropland, with manure runoff and failing septic systems also contributing to the problem. The increasing use of drain tiles—plastic pipes installed under farmland to remove excess water—has intensified the issue by carrying excess nutrients into surface waters.

Another source of pollution is urban runoff. In cities and towns, rain and snowmelt can carry leaves, dirt, trash, chemicals, and other pollutants into storm drains and nearby lakes, rivers, and streams. The transportation system can also impact water quality, with salt used on roads and parking lots draining directly into surface waters.

Groundwater contamination is also a concern, with PFAS contamination affecting the drinking water supplies of over 140,000 Minnesotans. Other sources of groundwater contamination include underground tanks at gas stations and landfills, which can leak and release pollutants into the soil and groundwater if not properly managed.

To address these issues, Minnesota has implemented policies like the Clean Water Act and is working to improve cropping systems, reduce farm runoff, and protect wetlands, which are vital for stormwater retention, water filtration, and wildlife habitat.

Impaired Waters List

Minnesota's water bodies have come a long way since the days when raw sewage flowed into its rivers and lakes. However, there is still work to be done to restore and protect its waters. As required by the federal Clean Water Act, the Minnesota Pollution Control Agency (MPCA) assesses all waters of the state and creates a biennial list of bodies of water that fail to meet water quality standards—the Impaired Waters List.

In 2022, 305 water bodies and 417 impairments were added to the list. In total, there are 2,904 water bodies with 6,168 impairments in Minnesota. Unhealthy conditions for fish and bugs are the most common impairments. The Impaired Waters List is used to set pollutant-reduction goals needed to restore impaired waters, called the total maximum daily load (TMDL). The TMDL establishes the maximum amount of a pollutant allowed in a waterbody and serves as the starting point or planning tool for restoring water quality.

The 2018 Impaired Waters List showed that excess mercury in fish tissue—a leading cause for fish consumption advisories throughout Minnesota—remains the largest single cause of impairments in the state's waters (31%). Other major causes of impairments include excess nutrients (14%), excess bacteria (14%), poor fishery health (13%), poor aquatic macroinvertebrates health (12%), and excess sediment pollution (7%).

The MPCA, in partnership with the DNR, is actively cleaning up PFAS groundwater contamination covering over 150 square miles, affecting the drinking water supplies of over 140,000 Minnesotans. More than 70% of nitrate pollution in Minnesota waters comes from cropland. The problem is intensified by the increasing use of drain tiles—plastic pipes installed under farmland to remove excess water from subsoils. Excess sediment, fertilizer from farm runoff, bacteria, and excessive river flows make the Minnesota River unhealthy. Nitrate pollution, primarily from excess farm runoff, continues to increase and poses risks to human health and aquatic life.

Water quality standards

WQS consist of three core components: designated uses of a water body, criteria to protect designated uses, and antidegradation requirements to protect existing uses and high quality. States, territories, and authorized tribes must specify goals and expectations for how each water body is used. Typical designated uses include protection and propagation of fish, shellfish, and wildlife, as well as agricultural, industrial, navigational, and other purposes.

Water quality criteria can be numeric or narrative. Numeric criteria provide a specific numeric threshold, such as the maximum pollutant concentration levels permitted in a water body. A narrative criterion, on the other hand, describes the desired conditions of a water body, such as being "free from" certain negative conditions. For example, in New York State, nutrients are regulated by a narrative water quality standard. The narrative standard for phosphorus and nitrogen is "none in amounts that result in the growth of algae, weeds, and slimes that will impair the waters for their best usages."

States, territories, and authorized tribes may also adopt policies and provisions that generally affect the application and implementation of water quality standards, such as WQS variance policies/procedures, mixing-zone policies, and low-flow policies. These policies are subject to EPA review and approval.

In Minnesota, about 40% of the state's waters fail to meet basic health standards, according to state water quality reports. The Minnesota River, for example, suffers from excess sediment, fertilizer from farm runoff, bacteria, and excessive river flows that make this 332-mile major tributary unhealthy. The Mississippi River and its tributaries are cleaner today than they were 30 years ago, but challenges remain. Much of the polluted water is in western and southern Minnesota, where agriculture is most intense. Excess soil and nutrients from farm fields can harm aquatic life.

To address water pollution, the Minnesota Pollution Control Agency (MPCA), in partnership with the DNR, is actively cleaning up PFAS groundwater contamination covering over 150 square miles, affecting the drinking water supplies of over 140,000 Minnesotans. The MPCA also assesses all waters of the state every two years and creates a list of bodies of water that fail to meet water quality standards—the Impaired Waters list. In 2022, 305 water bodies and 417 impairments were added, bringing the total to 2,904 water bodies with 6,168 impairments in Minnesota.

Drinking water safety

Minnesota has a safe, reliable, and affordable supply of drinking water, but this is no accident. It requires the efforts and teamwork of many people, including government officials, water utility operators, and the public, to make it possible to maintain the confidence we have in the water from our taps. The Minnesota Department of Health (MDH) is the state authority for drinking water and has several programs in place to ensure safe and adequate drinking water.

The Drinking Water Protection program focuses on public water systems, which serve 25 people or more in places where they live, work, gather, and play. MDH works to ensure the safety of drinking water from public suppliers by monitoring water quality, performing inspections, and establishing design criteria. MDH coordinates with other state agencies to determine what types of contaminants a particular water system may be susceptible to. For example, surface water suppliers are required to include filtration and disinfection in their treatment processes as final barriers of defense against contaminants.

The MDH Drinking Water Program includes monitoring drinking water quality, performing sanitary surveys, and establishing construction standards. MDH collects and analyzes water samples to determine if disease-causing organisms and toxic chemicals are present. If unacceptable levels of contamination are found, MDH works with the supplier to alert the public and take corrective action. MDH also performs on-site inspections of a water system's facilities and operations and sets construction standards for any kind of water treatment project.

The federal Safe Drinking Water Act (SDWA) contains National Primary Drinking Water Regulations, which are legally enforceable standards and treatment techniques that apply to public water systems. The Safe Drinking Water Act defines a contaminant as anything other than water molecules. Drinking water typically contains at least small amounts of some contaminants, but the presence of contaminants does not necessarily mean that the water poses a health risk. If a contaminant is present above a particular level, then it may cause harmful health effects.

In Minnesota, about 40% of waters fail to meet basic health standards, with the Minnesota River being one of the most polluted. The main sources of pollution are excess sediment, fertilizer from farm runoff, bacteria, and excessive river flows. However, the state is actively working to improve water quality, and major improvements in cropping systems and pollution controls will be needed to restore the river to health.

Water conservation efforts

One of the key water conservation efforts in Minnesota is the work of the Minnesota Pollution Control Agency (MPCA). The MPCA is dedicated to protecting and restoring water quality through intensive water-quality monitoring. They assess the state's waters every two years and create the "Impaired Waters List", which identifies water bodies that do not meet water quality standards. This list helps develop studies and plans to restore these waters. The MPCA also works to educate the public, local governments, and businesses on pollution prevention, waste reduction, and sustainable practices.

Another important initiative is the Minnesota Nonpoint Source Management Program Plan, which addresses non-point source pollution in water. Non-point sources include precipitation runoff from farm fields, sediment from eroding streambanks, and faulty septic systems. The program provides guidance for federal, state, and local planning efforts to control and reduce this type of pollution.

Clean Water Action is also playing a significant role in water conservation in Minnesota. They have been working since 1982 to find solutions to environmental and community problems, develop community-based environmental leadership, and advocate for policies that protect water resources. One of their programs, ReThink Disposable, aims to shift the culture away from single-use disposable items towards reusable and sustainable alternatives. Additionally, their Sustainable Feed, Sustainable Food program aims to implement policies that reflect sustainable practices in livestock production to protect natural resources, including water.

Furthermore, the Minnesota Department of Natural Resources plays a crucial role in groundwater management. They issue permits to users of large amounts of groundwater and have a Nitrogen Fertilizer Management Plan to prevent and minimize the impacts of nitrogen fertilizer on groundwater. Additionally, the Department of Agriculture is addressing groundwater depletion in the Twin Cities metropolitan area through its Water Supply Plan.

Overall, these water conservation efforts in Minnesota are focused on monitoring water quality, educating the public and stakeholders, implementing policies and plans to reduce pollution, and advocating for sustainable practices. By combining these approaches, Minnesota aims to protect its valuable water resources and ensure their long-term sustainability.

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