Ron Mergen, Paynesville Public Works Director, cautioned home owners with shallow wells. There is a possibility of surface water contamination, especially in old hand dug wells. “A lot of them have been sealed up but there are still a few found in rural areas,” he added. “The newer wells are sealed pretty tight, but can still get contaminated.”
Contaminated drinking water wells are a major concern of the Minnesota Department of Health. At the same time, simply coming in contact with flood water shouldn’t pose any significant risk of infectious disease, health officials emphasized.
“Our primary concern is private drinking water wells,” Anne Barry, state health commissioner, said. “Private well owners should assume their wells are contaminated if the flood waters have come within 50 feet of the well casing. That means your well will have to be flushed out, disinfected and tested before you can start using the water again,”
Allen Anderson, Thein Well, Paynesville, urged every home owner whose well was covered by water to have the wells tested and disinfected. “It won’t necessarily be contaminated but it could be, as most wells have a vented well cap. If a well is properly constructed groundwater and normal rain fall is not a threat. But standing flood waters does pose a threat. Any time there is a potential for contamination, have the well tested and probably disinfect it any way. It is a good policy to disinfect a well once a year,” he added.
Any contaminated water used for drinking or cooking must be boiled at a rolling boil for at least five minutes. Every time water is used, the water must be boiled. Homeowners will need to repeat this daily until the well and entire plumbing system has been disinfected and tested.
Adding a laundry bleach or granular chlorine is a common procedure to disinfect a well. (Commercial chlorine can be purchased locally from well drillers or plumbing contractors; laundry bleach can be purchased at any grocery, hardware, or convenience stores).
Al Neu, owner of Neu’s Pure H2O, Paynesville, said homeowners who need to disinfect their wells also need to give their home water system a shock treatment. After pouring the chlorine or bleach into the outside well, turn on your cold water faucet until you smell chlorine. Repeat this with every faucet in the house, plus the dishwasher, bathroom stools and automatic dishwashers. Once all the cold faucets have been done, repeat the procedure with the hot water faucets. This shock treatment will clean and disinfect the waterlines throughout the house.
Private well owners who anticipate flooding may want to seal up their wells before the floods arrive. Sealing wells won’t necessarily prevent contamination, or eliminate the need for disinfection. However, it can still make the post-flood clean-up go more smoothly by keeping sediment and debris out of the well.
Health department officials offer these suggestions if you think your well may be flooded:
• Before you take your well out of service, fill up a number of containers with a supply of clean water, for use during the flood, if you have time.
•Disconnect the power supply from your well.
•If you have time, get a well contractor to install a water-tight seal on your well, replacing the regular cap or seal.
•If you don’t have time to get your well professionally sealed, clean off the outside of the well casing and cover it with a heavy duty trash bag or some other form of heavy plastic sheeting.
If the top of your sewage treatment tank was under water, it must be pumped out to remove all solids and liquids, before you can run sewage into it again. Pumping stations and drop boxes should also be pumped out, advises the health department.
“You should always assume that flood water is contaminated,” Barry said. “A person should wear rubber boots and rubber gloves if you need to work around flood water or sewage, and a person should wash up thoroughly with soap and water when they are done.
If a person is unsure, call your local well drillers for advice, or the Stearns County Environmental Services Department, 1-800-450-0852. They would be happy to answer any questions you might have.