NC wells contamination has spiked after floods
Don’t drink the well water. That might well be the warning notice left by Hurricane Florence.
Contamination of private water wells in North Carolina has spiked in the aftermath of flood waters that spread raw sewage, farm animal waste and the overflow from septic systems across parts of the state, according to data from N.C. Department of Health and Human Services.
Because private wells are largely unregulated in North Carolina, there is no comprehensive data available on the levels of contamination caused by hurricane flooding. But scattered information from free testing provided by the department suggests that thousands of homeowners could be unwittingly using contaminated water for drinking, cooking and bathing.
The National Ground Water Association estimates that 332,798 private wells in North Carolina were exposed to heavy rains or are located in counties declared disaster areas from the hurricane. About 2.4 million people in the state get their drinking water from wells in their yards, the fifth-highest total in the nation, according a 2018 report by the U.S. Geological Survey.
Several hundred samples analyzed in recent weeks by the State Laboratory of Public Health show a marked increase in E. coli, the telltale bacteria that indicates the presence of fecal matter found in raw sewage and in animal waste.
Those samples come from the free water analysis being offered by the state to owners of private wells in 23 counties, to encourage getting wells tested. So far private well owners have submitted 646 water samples for testing, out of 2,165 sample free water testing kits distributed to county health departments.
The free testing is still being offered in the 23 counties, with an end date yet to be determined. These counties are in the southeastern section of the state that was soaked by Florence, and include several in or near the Triangle: Johnston, Chatham, Harnett and Lee.
The results as of Oct. 19 show that 14.9 percent of the well water tested positive for E. coli bacteria and total fecal coliform bacteria. That compares to just 2 percent of private wells testing positive for those same pathogens between January and September, before Hurricane Florence struck the state. The presence of these bacteria indicates that the water is contaminated with pathogens that can cause diarrhea, cramps, nausea and vomiting.
At least one county is seeing a corresponding increase in stomach illness, but the causes can’t be pinpointed exclusively to private wells. Columbus County averages three gastro-intestinal reports a month, but has received 11 reports since Hurricane Florence. The county has tested 57 water samples and 13 have come back positive for total coliform, while five were positive for total coliform and fecal matter, said county health director Kim Smith.
“I can tell you that we have had an increase in our reported cases of gastro illnessess,” Smith said by email. “Please keep in mind that gastro illnesses can be due to many causes not just contaminated water.”
In addition to the free testing, other free or discounted services are being offered to private well owners. The N.C. Ground Water Association is providing $100 to offset the cost of chlorinating and decontaminating a private well. So far there have been no takers, a source of frustration to the association, said Chauncey Leg- gett, the group’s president and a well driller in Tarboro.
The decontamination cost would typically run between $80 and $200, depending on the type of well and other factors, said Chuck Job, regulatory affairs manager at the National Ground Water Association. The process involves pouring bleach into the well, waiting up to 24 hours and retesting for bacteria about a week after the disinfection, according to an instructional manual from the U.S. Environmental Protection Agency.
And a group of scientists working with N.C. State Extension, UNC-Chapel Hill and Virginia Tech University took about 50 water samples last week for free lab analysis in New Hanover and Brunswick counties. The group plans to expand to other counties in the coming weeks, said Michael Burchell, a professor of biological and agricultural engineering at N.C. State University.
“It does matter that there’s double-digit contamination of bacteria,” Burchell said. “Those owners need to address that.”
The potential sources of the contamination include hog waste lagoons, which store urine and feces; according to state data, six of the lagoons were structurally damaged during the flooding and 33 overflowed. Contamination also can be traced to waste water treatment plants that overflowed and discharged millions of gallons of raw sewage into flooded rivers. Additionally, thousands of private septic systems could have disgorged human waste when they were submerged.
Bacteria can enter a private well through a crack or a gap, not uncommon in decades-old wells. Or the bacteria can seep into groundwater when the ground is saturated from heavy rain, and flow into the well.
Once it worms its way inside a well, E. coli can replicate and survive for more than a month, depending on the conditions, said Jacqueline MacDonald Gibson, a professor of environmental sciences and engineering at UNC.
Not everyone gets sick from ingesting the pathogens and microscopic bits of fecal matter. Some may feel under the weather for reasons unknown to them.
Others who get sick can have a severe reaction, requiring hospitalization.