In the News | Nitrate Risks in Karst Regions

SOUTHEAST MINNESOTA—Our region’s water quality issues haven’t changed – much. The threat to our underlying groundwater and wells or the Driftless Area’s surface streams and rivers, the health of our waters – and, ultimately, us – are ongoing concerns.

Increased awareness over the past year has led to more action being taken to address water quality and its relationship to nitrates – better education for homeowners and families, encouragement of nitrate ‘best practices’ on residential yards, fertilizer use on crop land and manure management in other agricultural settings.

But what has been in the news more recently are a request for public comment regarding Minnesota’s guidelines on groundwater protection; a new online presentation with an up-to-date overview of regional water contamination issues; and an invitation to farmers and others involved in agriculture to attend one of two University of Minnesota Extension informational meetings to discuss nitrogen research and best practices.

Public comment on groundwater protection

The Minnesota Department of Ag (MDA) has opened a public comment window to help determine whether the state’s Groundwater Protection Rule is adequate to protect Minnesota’s air, water, land and other natural resources from nitrate pollution.

Its evaluation of the plan is in response to a September 2025 order from the Ramsey County Second Judicial District Court instructing MDA to assess findings on whether the rule provides sufficient protection, or if additional restrictions are needed.

Southeast Minnesota’s karst topography creates unique challenges in protecting groundwater from surface contaminants. (Minnesota Department of Ag poster)

Adopted in 2019, the Groundwater Protection Rule is “designed to minimize nitrate contamination in vulnerable groundwater areas and protect drinking water sources,” according to the MDA. “The rule restricts nitrogen fertilizer application in the fall and on frozen soils. It also establishes a framework for reducing contamination in areas where public water supplies already are experiencing elevated nitrate levels.”

During the current public comment period, the MDA is requesting written public input that provides information on the following:

• Whether the Groundwater Protection Rule adequately protects against nitrate contamination from regulated practices; or
• Whether further restrictions should be applied to sensitive regions, including Southeast Minnesota’s karst geology and the state’s Central Sands region.

Responses should provide substantive information and supporting evidence; comments stating only support for or opposition to the rule will not assist the MDA in its decision-making.

For additional information or to file your comments, visit the MDA’s Groundwater Protection Rule Public Comment page. Comments must be received by Thursday, March 12, 2026.

Water contamination overview

“From Field to Faucet: Nitrate Risks in Karst Regions” – an online program presented in January – lays the groundwork for a general understanding of area water contamination issues, including tips for well owners to protect their drinking water from nitrate and other contaminants in southeast Minnesota’s karst landscape. 

(Cannon River Watershed Joint Powers Organization graphic)

Hosted by the Cannon River Watershed Joint Powers Organization, the presentation is now available for public viewing, part of its “Land to Lake Lectures” virtual-learning series.

According to its host, the presentation explores “nitrate contamination in well water, which can enter water from fertilizers and waste – a growing concern in southeastern Minnesota, where karst geology allows water – and pollutants – to move quickly from the surface into groundwater. High nitrate levels threaten human health and water quality.”

The program features Martin Larsen, a conservation and feedlot technician with Olmsted Soil & Water Conservation District, who explains how karst landscapes work; why they are vulnerable to nitrate pollution; and what landowners can do to protect drinking water. 

Well-water testing and conservation practices that reduce nitrate loss in soil are also covered in the session. 

Southeast Minnesota residents who rely on a private well for drinking water are also reminded that they can request a free water-testing kit through the state’s Tap-In initiative launched in 2024 from regional concern with high levels of nitrate in private wells. 

These kits test at no charge for nitrate, lead, manganese, arsenic and coliform bacteria. Eligible residents must live in one of Tap-In’s nine counties: Mower, Dodge, Fillmore, Goodhue, Houston, Olmsted, Rice, Wabasha or Winona.

Watch From Field to Faucet: Nitrate Risks in Karst Regions, above; for additional links and documents related to the presentation, visit the Land to Lake Lectures series homepage.

Addressing agricultural nitrate issues

University of Minnesota Extension (UMEX) is hosting two meetings for area farmers and those involved in agriculture to discuss the current situation. 

These are part of its Nitrogen Smart education series – in-person meetings focusing on agricultural land-use practices that maximize profitability while minimizing environmental losses.

“A multitude of issues related to nitrates in water in southeast Minnesota have come to the forefront over the past few years,” according to the meeting announcement from UMEX Educator Katie Drewitz. “This has led to a reexamination of how nitrogen fertilizer and manure are managed in the region.” 

To help land managers better understand the issues and possible solutions, UMEX is inviting those interested to attend one of two upcoming meetings – the first is in Fountain, Minn. on Monday, March 2, and the second is in Zumbrota, Minn. on Tuesday, March 3.

Topics covered include: 

• An update on the current regulatory and policy situation
• How nitrogen behaves in the environment and how it gets into water
• The dynamics of groundwater recharge in southeast Minnesota
• Best management practices for both commercial fertilizer and manure, based on local research
• On-farm nitrogen management research results in southeast Minnesota 

The meetings both days open with registration beginning at 8:30 a.m. and the program starting at 9:00 a.m. There is no charge, but preregistration is requested as lunch will be provided. 

For additional information or to register, follow one of these two links:

• Nitrogen Smart: Focus on southeastern Minnesota – Fountain
• Nitrogen Smart: Focus on southeastern Minnesota – Zumbrota