Flood Aftermath: Not a Drop to Drink

IowaWatch:

Contamination of private well water in southwest Iowa from human and natural causes is a problem even in dry times. But in this year of prolonged flooding, well owners have heightened concerns and are keeping county health officials busy testing water for contaminants such as coliform and E. coli bacteria, nitrates and arsenic. More well owners are availing themselves of the Iowa Department of Natural Resources program that pays for private well testing.

The flood has not caused a huge spike in levels of coliform and E. coli bacteria, nitrates and arsenic in the region, according to state and county environmental health officials interviewed by IowaWatch, but many well owners face challenges in keeping their water safe to drink.

After pumping four feet of water from their 15 year-old home’s basement, the Stephenses had to wait “until water quit shooting out of the top of the wellhead,” to get the well back in operation, Jamie Stephens said. The artesian effect was caused by hydrostatic pressure in the saturated soil around the well.

The Stephenses had the well tested twice in May and shocked it with disinfectants repeatedly, following recommendations from their county sanitarian.

In a text this past week, Stephens wrote: “We are still working on getting everything bad out of the water. Not drinkable yet. Shocked the well twice and waiting for the test results from the last shock to see if it’s clear to drink.”

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Intact wells are at risk for fouling by sediment and debris. Naturally occurring bacteria and iron can increase and nutrients applied as fertilizer can get into the aquifers, so great care should be taken to ensure water is safe to drink, Schnieders said.

Mills County’s Sukup and his Fremont County counterpart, Erman Mullins, said they haven’t seen that worst-case scenario play out. “I’m not seeing anything real bad,” Mullins said in late April. Of recent well tests, most showed coliform and E. coli bacteria levels at acceptable levels of at less than 1 milligram per liter and only one that’s been over 10 on nitrates.

A month later, two of 10 recent tests showed water over the acceptable bacteria levels and one with nitrates at 13 milliliters per liter, too high for exposure to infants.

Test results he’s seen over the last five years show that flood waters have affected some private wells, “but I’m not seeing anything that makes me think there is something really wrong,” Tell said.

In 2019, for example, the private well statewide average for tolerable rates of total coliform bacteria was 77.21%. Monona, Pottawattamie and Mills counties have tested in the 72% to 74% range. The same counties tested at equal to or above the state average for E. coli.

More alarmingly, rates for acceptable nitrate levels for infants fell well below the state average of 92.87% in three of the counties. Monona County came in at 85%, Harrison County at 86.21% and Mills County at 85.64%.

The state averages themselves are cause for concern. Nearly 23% of private wells tested in 2019 had higher than recommended levels of coliform bacteria, more than 3% were above the safe level for E. coli and more than 7% exceeded the safe infant level for nitrates.