The Des Moines, Iowa, Water Works announced it has already run its nitrate removal system 111 days in 2015. In comparison, the system was only run 106 days during the entire year of 1999. The requirement to lower the nitrate level in drinking water to 10 milligrams per liter is highly expensive and the basis for a lawsuit filed by the water works board against drainage districts in three northern Iowa counties.

The lawsuit is demanding mandatory nitrate reduction strategies rather than voluntary actions, mainly by farmers with field tiles draining into tributaries and ditches feeding into the Raccoon River, which is a source of water for Des Moines.

The water board is expecting costs for nitrate removal treatment and lost revenue to exceed $1 million in 2015.

Farm leaders have been arguing that farmers need time to implement voluntary strategies to reduce runoff of nutrients including phosphorus and nitrogen.