Community Public Water System Flooding Guidance - EH: Minnesota Department of Health

Community Public Water System Flooding Guidance

What to Do Now

Days and Hours Before Potential Flooding

  • Make sure to have enough treatment chemicals on hand to allow for possible delays in access or service.
  • Make sure all drinking water storage tanks are full, and ask any interconnected systems to do the same to maximize flexibility in response.
  • Shut the electrical power off to the well.
  • Wrap and tape well caps with heavy duty plastic to help reduce the opportunity for contaminants to enter the well.
    • Once a well is contaminated, it can be difficult to remediate. Some systems have had to seal a well after repeated attempts to remove contamination.
  • Protect any electrical or communications wiring or components vulnerable to flooding.
  • Sandbag to prevent any breaches to vulnerable critical infrastructure.

During and After Flooding

  • Call the State Duty Officer at 1-800-422-0798 and say, "My drinking water system has had a [describe flooding incident]."
    • The State Duty Officer is a message relay service and will notify the appropriate organizations for response, including the Minnesota Department of Health Drinking Water Protection (DWP).
    • DWP will contact you within minutes to discuss the situation, help with technical assistance, and follow through on coordinated response actions.
    • Any system can request MnWARN assistance when calling the State Duty Officer.
  • Work to keep the distribution system pressurized.
    • Once a system loses pressure, it is vulnerable to contamination from intrusion of groundwater, cross-connections and backflow.
  • Isolate any breached infrastructure by closing valves to minimize contamination of the rest of distribution system.
  • As a general precaution, in coordination with DWP, you may issue a Drinking Water Advisory. If critical infrastructure is breached, you must issue a Drinking Water Advisory.
    • The advisory can be limited to the affected area or apply to the entire distribution system if it is vulnerable to contamination.
  • Once flood waters have receded, DWP will work with you to get your system back to full operation. 
    • Once the system is fully pressurized, disinfected, and flushed, DWP will help collect water quality samples to determine when to lift a Drinking Water Advisory.

Learn more at Drinking Water Safety in Emergencies.

Updated Wednesday, 27-Jul-2022 09:53:19 CDT