Requirements and Recommendations for Public Water Suppliers
Source Water Protection

All PWS supplying groundwater must manage the land adjacent to their wells. The 200 foot radius around the well is the Inner Wellhead Management Zone (IWMZ). MDH conducts a IWMZ survey with public water suppliers during the wellhead protection planning process (for community systems) or during a sanitary survey (for noncommunity systems). The results of the survey are in the wellhead protection plan or the sanitary survey. Public water suppliers who have had a IWMZ survey conducted must:

• Maintain the isolation distances defined in the state Well Code (Minnesota Rules, Chapter 4725) for proposed potential sources of contamination.
• Monitor existing potential sources of contamination that do not comply with the isolation distances defined in the state Well Code.
• Implement wellhead protection measures for potential contaminant sources in the Inner Wellhead Management Zone.

MDH will contact a PWS when staff are ready to start the planning process or amend a plan. MDH provides plan development assistance for all PWS in the wellhead protection program. Assistance varies depending on the size and type of the PWS. The basic requirements of developing and implementing a wellhead protection plan are:

• Delineate the Wellhead Protection Area (PDF) and determine the Drinking Water Supply Management Area (DWSMA). The DWSMA is the area on the land covering the groundwater that could flow to the well within 10 years.
• Conduct a vulnerability assessment (PDF) to determine how protected the water supply is. Vulnerability factors in the geology and well construction. Conceptual models of wellhead protection areas in a High Vulnerability with Direct Surface Water-Groundwater Interaction Setting (PDF) and a Low Vulnerability Setting (PDF) can help illustrate this concept.
• Groundwater Model Calibration Policy (PDF)
• Inventory potential sources of contamination and other threats within the DWSMA.
• Identify activities to reduce the risk from potential sources of contamination and other threats to the water supply.
• Develop a plan for an alternative supply in case of contamination or mechanical failure.
• Report on plan progress to MDH.
• Vulnerability Assessment Parameters Factsheet (PDF)
• Land Cover and Associated Potential Contaminants Sources (PDF)

New Municipal Well Form (PDF): All public water suppliers (or their consultants) must submit a preliminary delineation of the wellhead protection area for any proposed new municipal well and an assessment of the impacts that existing land and water uses located within this area may have on the aquifer serving the well. These requirements are part of These requirements are part of plan review for wells.

Determination of Aquifer Properties and Aquifer Test Plan (DAP-ATP) Form (PDF): Community and nontransient noncommunity public water suppliers (or their consultants) delineating a Wellhead Protection Area (WHPA) must submit existing data on the aquifer or a plan to collect the data with an aquifer test prior to delineating the WHPA. The Aquifer Test Information Form may be helpful for documenting basic information during an aquifer test.

PWS supplying surface water should consider developing surface water intake protection plans. Surface water intake protection plans are not required by law, but some PWS in Minnesota have developed voluntary plans to protect their drinking water source. Other PWS supplying surface water have expressed interest in developing plans.

MDH is currently updating the framework in consultation with PWS and other stakeholders. The goal is to make resources more available to PWS who want to develop plans.