Private well owners reminded to check for water contamination after flooding

Flooding in eastern South Dakota could impact the water in privately owned wells.

That is according to Christopher Hay, South Dakota Cooperative Extension water management engineer, who said owners should be aware of the risks of water contamination that flooding poses.

"Floodwaters often carry hazardous or toxic materials, including bacteria, viruses, other pathogens, petroleum products, pesticides, and other chemicals," said Hay. "Wells that have been partially or fully submerged by flood waters can become contaminated with these materials, and drinking or washing with water from a private well that has flooded exposes people to risk of disease."

Hay said that if your well has been flooded, the well should be disinfected to remove bacteria once the floodwaters recede. "It should then be tested to ensure it is safe, and if testing is delayed, the water should be boiled for at least 1 minute at a full rolling boil to temporarily treat it until testing and disinfecting are completed," Hay said. "Household water treatment systems will not provide enough protection and will also need to be disinfected."

Hay said well owners should inspect their wells prior to disinfection. "First, make sure the electricity to the pump is turned off and that the electrical system is completely dry," said Hay. "Any damage should be repaired by a qualified electrician, well contractor, or pump contractor." If the well cap is off or the well casing is damaged, large amounts of sediment and other debris may have entered the well. In that case, Hay said, owners should call certified well contractors to inspect wells.

"If the well cap is still on the well and not damaged, remove it and examine the inside of the well for damage," said Hay. "If the inside of the well casing is clean and there is no damage to the wiring, pump, or piping, the well can be disinfected using shock chlorination."

Shock chlorination is relatively easy and can be done by the well owner, but Hay said owners may prefer to have a well contractor complete the disinfection. "Instructions on shock chlorination and links to more information can be found at the South Dakota Water Resources Institute website," Hay said. That site is http://wri.sdstate.edu/flooding.cfm, or ask for the information, available on DVD, at your county Extension office.

The South Dakota Cooperative Extension Service flooding website also has the information. That site is http://sdces.sdstate.edu/flood/.

Hay said that after the shock chlorination treatment, owners should collect a water sample and have it tested for bacteria. Sample bottles can be obtained from your county Extension office or at the South Dakota Water Resources Institute on the campus of South Dakota State University in Brookings. Two follow-up tests, one after two weeks and another after three months, will ensure that the well has been completely disinfected.

The South Dakota Water Resources Institute can answer questions about other possible contaminants. To reach the office, call 605-688-4910. More information on collecting and submitting water samples can be found at the website: http://wri.sdstate.edu/collecting_submitting.cfm.