Des Moines residents asked to reduce water use due to nitrate levels

DES MOINES – Des Moines Water Works asked its customers in central Iowa on Thursday to reduce the amount of water they use, after officials determined demand would outpace the ability to treat persistently high nitrate concentrations from nearby rivers.

The utility said the highly polluted water in the Raccoon and Des Moines Rivers had forced them into “unprecedented circumstances” that meant decreasing the amount of water being used by customers, which is currently 70 million gallons per day and increasing.

“Absent an extraordinary situation, it’s not a good business model to ask customers to reduce their demand for water,” said Bill Stowe, CEO and general manager of Des Moines Water Works, in a statement. “It’s a decision we have arrived at only after much thought, both in terms of the inconvenience to our customers and the impact to our revenue base.”

The record-setting concentrations in the rivers require extensive treatment at a nitrate removal facility that’s operating at maximum capacity at a cost of $375,000 as of the end of June. The utility has been using alternate sources of water with lower levels of nitrate, but they’re not adequate to meet customer demand, the utility said.

The water reduction efforts include customers limiting the time sprinklers are on and watering their lawns and plants on odd or even days. Des Moines Water Works said if water use does not decrease, the utility will be unable to meet the maximum contaminant level for nitrate set by the Environmental Protection Agency, which is 10 milligrams per liter. The high nitrate levels were caused by the state’s soggy spring following a drought. A deluge in water washed fertilizer off the farms and into rivers that provide drinking water. High nitrate concentrations can cause the greatest health risk in infants under 6 months, though Des Moines Water Works says treated drinking water has not reached a nitrate level that will cause health problems.