News | April 30, 2014

Household Water Well Owners Should Inform Themselves About Flood Threats

There are certain things household water well owners should know during this flood season about how to protect their wells and their water quality, the National Ground Water Association said recently.

Flooding by surface water can threaten groundwater quality and the condition of a well system. The vulnerability of a well can vary depending on the area in which one's property is located or even the specific spot on a parcel of property where the well is installed, said Cliff Treyens, National Ground Water Association public awareness director.

Following are steps household well owners can take before, during, and after a flood to prevent, minimize, or recover from well flooding.

Before a flood threatens

Assess the water well to determine if it might be vulnerable to flooding. Considerations include:

  • Wellhead location -- is it on high ground, which is least vulnerable to flooding; flat ground; or low-lying ground, which is most vulnerable to flooding?
  • Construction -- is the well constructed to meet applicable codes or regulations, such as the proper height for the well casing and proper grouting of the well casing to minimize the potential for floodwater infiltration?
  • Seals -- are the well system's sanitary seals intact to resist floodwater infiltration?

When flooding is imminent

Ask a water well system professional what precautions should be taken, if any, to minimize the chances of floodwater entering the well. Also, well owners who are vacating their property due to flooding should shut off the power to the well pump before leaving.

After well flooding

Household water well owners should call a contractor for an assessment of the well system.

Arrangements for an alternative water supply such as bottled water should be made until the well has been cleaned, serviced, disinfected, tested, and the water proven safe to drink.

Well owners should not attempt to service their wells due to safety risks, including electrocution, and the potential to create more damage.

Even under normal circumstances, proper disinfection of a water well can be difficult for the untrained. The proper type and amount of disinfectant, its distribution throughout the system, contact time with the water and well components, and the well's cleanliness can impact the effectiveness of water well disinfection.

When a well is flooded, disinfection can become even more problematic due to the introduction of organic matter into wells, which can react with disinfectants to create disinfection byproducts considered a health risk.

Flooding may cause debris to enter the well, requiring a thorough cleaning of the well system.

Also, because floodwater can pick up some of whatever is on the ground surface -- or contain substances that have spilled into the floodwater, such as chemicals in storage bins or tanks -- disinfection of the water well may not be enough. Extensive pumping of the well and the aquifer may be required to eliminate contamination. After a flood emergency, check with local emergency officials or the county health department about any area-specific water testing that should be done.

For all these reasons and more, it's recommended a qualified water well system contractor should be engaged to inspect, service, clean, and disinfect a well after a flood. Water testing should be done by a certified drinking water testing lab.

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About NGWA
NGWA, a nonprofit organization composed of U.S. and international groundwater professionals -- contractors, equipment manufacturers, suppliers, scientists, and engineers -- is dedicated to advancing groundwater knowledge. NGWA's vision is to be the leading groundwater association that advocates the responsible development, management, and use of water.

SOURCE: National Ground Water Association