Facing escalating costs to denitrify its drinking water, taken from the Raccoon River, the Des Moines Water Works is suing three upstream counties over nitrate levels in the river. The utility provides drinking water for 500,000 urban and rural customers in central Iowa. To meet federal standards, it had to denitrify its water for a record 148 days in one year, according to Bill Stowe, CEO and General Manager of the utility. That’s up from the previous record of 108 days.Stowe recently spoke in St. Paul and Mankato as part of a lecture series held by the Freshwater Society.The utility is suing three Iowa counties and their drainage districts, alleging they discharge nitrate pollutants into the river, and fail to obtain a National Pollutant Discharge Elimination System (NPDES) permit in violation of the Clean Water Act. The complaint seeks to declare the drainage districts as “point sources,” meaning they are subject to regulation and required to have a permit under federal and Iowa law.The utility chose to sue because it is spending more than $1 million a year to denitrify its drinking water to safe consumption levels. If nitrate trends in the Raccoon River continue to climb, then the utility will need to build a new denitrification facility, estimated to cost between $76 million and $183 million.According to news reports, Iowa farm leaders say solutions like cover crops and bioreactors that reduce nitrogen leaching take time to get in place. Also, the law firm representing the counties argues that the drainage districts have no power to direct how landowners use or manage their properties, nor control over what goes through the drainage tiles.The lawsuit is scheduled to be heard in federal court in Sioux City in August 2016. Photo: Bill Stowe, right, answered questions following his talk.