NGWA Reports Nearly 729,000 Households On Wells Potentially Affected By Flooding In Early 2020

Exposure to E. coli and coliform possible in flooded locations.

The National Ground Water Association (NGWA) reports nearly 729,000 households relying on wells were potentially affected in counties with flooding in 10 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 10 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 percent to 45 percent 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.

The breakdown of households with wells potentially affected by flooding in the abovenamed 10 states are as follows, with the number of impacted counties listed first, followed by the number of households with a well source, and, lastly, the estimated number of wells with flood impact:

• Alabama — 67 counties — 201,111 households — 20,110 wells
• Georgia — 121 counties — 347,566 households — 34,760 wells
• Hawaii — 1 county — 236 households — 20 wells
• Illinois — 4 counties — 9,866 households — 990 wells
• Michigan — 1 county — 9,677 households — 970 wells
• Mississippi — 3 counties — 2,623 households — 260 wells
• North Carolina — 17 counties — 126,544 households — 12,650 wells
• North Dakota — 21 counties — 17,771 households — 1,780 wells
• Oregon — 1 county — 6,975 households — 700 wells
• Virginia — 1 county — 6,498 households — 650 wells.

The above totals result in 237 counties, 728,867 households, and 72,890 wells possibly being impacted.

NGWA offers a flooding resource center at WellOwner.org. 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.

WellOwner.org is a joint venture of NGWA and the Rural Community Assistance Partnership as part of the U.S. EPA-funded program “Improving Water Quality through Training and Technical Assistance to Private Well Owners.”

Sources: Online state flood reports; federal and state disaster declarations; and online local news reports.

* Based on last census with representative results for household water sources outside metropolitan areas nationwide: 1990 American Housing Survey.

** In some cases, a domestic well may supply more than one household.

** National Ground Water Association. 2002. Field Evaluation of Emergency Well Disinfection for Contamination Events; Final Project Report for U.S. Federal Emergency Management Agency, Washington, D.C.

About National Ground Water Association
The National Ground Water Association is a not-for-profit professional society and trade association for the global groundwater industry. Our members around the world include leading public and private sector groundwater scientists, engineers, water well system professionals, manufacturers, and suppliers of groundwater-related products and services. The Association’s vision is to be the leading groundwater association advocating for responsible development, management, and use of water.