The MDA Updates Fall Nitrogen Fertilizer Restrictions Map

Map helps farmers prepare for 2026 groundwater protection requirements

St. Paul, Minn.: The Minnesota Department of Agriculture (MDA) has published an updated map to assist farmers across the state comply with the Groundwater Protection Rule. The rule restricts fall application of nitrogen fertilizer in areas vulnerable to groundwater contamination and outlines steps to reduce contamination where nitrate levels already are elevated in public water supply wells.

The MDA has made updates to the Fall Nitrogen Fertilizer Application Restrictions Map, available on the MDA website. One Drinking Water Supply Management Area (DWSMA) was removed from the map, and one was added. The Pine River municipal DWSMA was removed because its high‑nitrate well will no longer be used as a primary source. The Belle Plaine DWSMA in Scott County was added after the Minnesota Department of Health identified elevated nitrate levels. It will be listed as Delayed for Good Cause under the Groundwater Protection Rule. Additional information on fall application restrictions and exceptions is available on the MDA’s website.

Two Mitigation Level changes also were made, although they do not affect the map. The Goodhue municipal DWSMA moved from Delayed for Good Cause to Mitigation Level 1. The Valley Mobile Home Park non‑municipal DWSMA was removed from mitigation because it has not recorded nitrate concentrations at or above 5.4 mg/L in the past 10 years. More information is available on the MDA’s Mitigation Level Determination page.

Restrictions on fall nitrogen fertilizer application in affected areas will take effect on Sept. 1. Farmers are encouraged to review the updated map to determine whether their fields fall under these requirements.

For more information on the Groundwater Protection Rule visit www.mda.state.mn.us/nfr.

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