High Hazard Cross Connections in Minnesota

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In response to the federal Safe Drinking Water Act Ground Water Rule and recent incidents in Minnesota, the Minnesota Department of Health (MDH) has adopted high-hazard cross connections that are not adequately protected as a Significant Deficiency for all Community Public Water Systems (CPWSs).

For the purposes of CPWS Unit program implementation, SDs will be defined as high-hazard cross connections that need a Reduced Pressure Zone (RPZ) backflow preventer or air gap to meet the Minnesota Plumbing Code.  However, CPWSs can adopt a more comprehensive approach, addressing all cross connections as part of a cross connection control program.

Plumbing cross connection contamination incidents occur throughout Minnesota, in both large and small communities.  Below is a sample of cross-connection contamination events at CPWSs identified during MDH Drinking Water Emergency Responses: 

June 2009 Metro Area Population 85,000 Ethylene glycol
April 2011 Metro Area Population 390,000 Ethyl ether
Incidents have also occurred in small to medium-sized communities in Minnesota.


As of July 1, 2011, MDH District Engineers are working with CPWSs to start identifying high-hazard cross connections that are not adequately protected.  These Significant Deficiencies have the potential to cause introduction of contamination into finished drinking water, and are not allowed under the Minnesota Plumbing Code.

Many CPWSs already have established programs for monitoring high-hazard cross connections in their water distribution system.  MDH is working with the Minnesota Department of Labor and Industry (DLI), League of Minnesota Cities (LMC), Minnesota Section of American Water Works Association (MNAWWA), Minnesota Rural Water Association (MRWA), local plumbing code authorities, and the plumbing industry to establish resources and rule language to help all CPWSs in addressing inadequately protected high-hazard cross connections.

These organizations are available to provide the following resources:

  1. Provide information to elected officials and CPWSs regarding the threats and liabilities (public health and economic) associated with drinking water contamination due to inadequately protected high-hazard cross connections, i.e. fact sheets, website resources, workshops [LMC, AWWA, MRWA, MDH, DLI, and local plumbing code authority];
  2. Provide municipalities guidance for writing and adopting cross connection control ordinances [LMC, AWWA, MRWA, MDH, DLI, and local plumbing code authority];
  3. Provide licensed boiler operators with training and spring/fall reminder letters regarding the importance of cross connection control during boiler maintenance [DLI and MDH];
  4. Require local plumbing code authorities to forward received copies of all RPZ backflow preventer installation and maintenance records to the PWS [local plumbing code authority and DLI];
  5. Provide CPWSs with templates for tracking high-hazard cross connections with RPZ installation and maintenance records, i.e. spreadsheet and postcard notices [MRWA and LMC]; and
  6. Provide CPWSs with enforcement resources to address high-hazard cross connections that are not adequately protected including:
    1. ordinance language for enforcement and adopting any necessary fines [MRWA and LMC];
    2. fact sheet listing responsible authorities [MDH];
    3. assistance from enforcement authorities [regulatory authorities for licensed businesses; local plumbing code authority, DLI, and MDH].

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Updated Monday, November 04, 2013 at 09:49AM