NGWA Reports over 729,000 Households on Wells in Counties Potentially Affected by Flooding in Early 2020


Exposure to E. Coli and Coliform Possible in Flooded Locations

The National Ground Water Association (NGWA) reports over 729,000 households relying on wells potentially affected in counties with flooding in ten states during a series of late winter-early spring 2020 storms. The household count includes those on domestic wells in 237 flooded counties across the United States, per Census Bureau data*.  The states include Alabama, Georgia, Hawaii, Illinois, Michigan, Mississippi, North Carolina, North Dakota, Oregon and Virginia.



The Association says that based on the results of an earlier detailed study of wells flooded by Hurricane Floyd in 1999 in ten North Carolina counties, the number of domestic wells potentially affected by floodwater in the flooded counties may be as many as 10 percent of the number of well-water-supplied households** in the counties experiencing flooding***.

These figures, based on one study, are not statistically representative but give an approximation of wells potentially affected by flood events.  In this case, a worst-case estimate of up to 72,890 domestic wells across the country may have been affected by flood events from February to May of 2020.

Of greatest concern is the possibility of well contamination from floodwaters carrying pathogens and chemicals.  Exposure to E. coli, coliform, and other pathogenic microbes from human and animal fecal matter may occur following a major flooding event.  Household, farm, and small business wells situated in the broad rolling countryside and near streams and ponds could be standing in water for several days, raising potential health concerns if the well isn’t properly maintained.

Based on past flood events over large areas of the Midwest and Southeast United States, laboratory testing documented a range of 17% to 45% of samples from domestic wells testing positive for fecal contamination.

“Major concerns about well conditions affected by high water are that wells having wellheads that are cracked or faulty or have been damaged by flood debris may allow contaminated floodwater into the well,” said Chuck Job, NGWA regulatory affairs manager who compiled these data.

NGWA offers a flooding resource center at Within this site, well owners can connect to certified contractors in their respective communities nationwide, as well as gain knowledge on how to test, tend and treat well systems, before and after a flooding event.

Households with Wells Potentially Affected in 10 States and Tribe with Flooding in 237 Counties


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