The proposed Groundwater Protection rule minimizes potential sources of nitrate pollution to the state’s groundwater and protect our drinking water. The proposed rule restricts fall application of nitrogen fertilizer in areas vulnerable to contamination, and it outlines steps to reduce the severity of the problem in areas where nitrate in public water supply wells is already elevated.

Proposed rule documents

*A number of web addresses in the proposed rule have recently changed. Please view the Updated Links (PDF) to access the references listed.


Proposed Rule

The proposed rule contains two parts. Each part contains separate criteria and requirements. Depending on where you farm, you may be subject to one part of the proposed rule, both parts, or none at all.  

The proposed rule is intended to promote appropriate nitrogen fertilizer Best Management Practices (BMPs) and to involve local farmers and agronomists in adopting the most current science based and economically viable practices that can reduce nitrate in groundwater.  These other practices are called alternative management tools (AMTs).

Part 1 of the proposed rule

Part 1 of the proposed Groundwater Protection rule focuses on restrictions to fall application of nitrogen fertilizer if you farm in 1) an area with vulnerable groundwater or 2) those protection areas around a public well, known as a drinking water supply management areas (DWSMA), with high nitrate.

Vulnerable Groundwater Areas are determined by coarse textured soils, shallow bedrock, or karst geology and are designated by quarter sections. An entire quarter section is included if 50% or more of a quarter-section is considered vulnerable.

Notification of areas subject to fall application restrictions under Part 1 of the proposed rule would occur in January 2020.  Restrictions would take effect in September 2020.

Part 2 of the proposed rule

Part 2 of the proposed rule responds to DWSMAs which already have elevated nitrate. The goal is to take action to reduce nitrate in groundwater before a public well exceeds the health standard for nitrate. The proposed rule is structured using a sliding scale of voluntary and regulatory actions based on the concentration of nitrate in the well and the use of the BMPs. The MDA will form a local advisory team with farmers, agronomists and other community members. This team will be involved in reviewing, considering and advising the MDA on appropriate practices or requirements to reduce nitrate in the DWSMA. 

There are four mitigation levels used to determine voluntary and regulatory actions, two voluntary levels and two regulatory levels. All areas will begin at a voluntary level and move to regulation only if BMPs are not adopted or if nitrate contamination in the groundwater increases.

The earliest possible regulation under Part 2 of the proposed rule could be three years after the proposed rule takes effect and after a DWSMA is determined to meet the criteria for level 2.

Additional Resources