The three counties that Des Moines Water Works sued over nitrate pollution in the Raccoon River system have officially responded, and their message is simple:

It isn’t our fault.

Sac, Buena Vista and Calhoun counties oversee drainage districts in northwest Iowa. Water Works runs a water-treatment plant in Des Moines that serves nearly 500,000 customers and includes a special facility that removes nitrate pollution. Nitrate, which has been linked to blue-baby syndrome and other illnesses, can come from farm fertilizers, sewage, the air, decaying plants and other natural sources.

Water Works spent nearly a year documenting high nitrate levels in the three counties’ drainage districts, and says there are no other significant sources of nitrate besides farms in that area. The utility also has noted that it has run its $7,000-a-day nitrate removal system a record number of days this year, and that the system needs to be replaced.

Water Works sued the counties in March in U.S. District Court in Sioux City, arguing that the drainage districts are “point sources” of water pollution that should be regulated under the federal Clean Water Act.

In an answer filed in court May 22, the counties, through their lawyers at Belin McCormick P.C., said they are not subject to the Clean Water Act. They also denied they are the source of nitrate polluting Des Moines’ water supply. “Defendants deny that the drainage districts have taken any actions that detrimentally impact” Des Moines Water Works, the lawyers wrote.

The case has national ramifications and has drawn fierce opposition from agricultural interests in Iowa, which has 3,000 drainage districts. The matter now enters a discovery phase of the litigation. A preliminary hearing is set for December.

In court documents, the counties flatly denied the drainage districts contributed nitrate that polluting the Des Moines water supply and the Gulf of Mexico, where corn fertilizers have been blamed for a summertime dead zone that disrupts one of the nation’s most lucrative fisheries.

 “Defendants admit water quality always is an issue, deny that they are responsible for any such pollution, (and) deny that they are proper parties to address such issues,” the response reads.

The counties also deny that agricultural drainage is a “major contributor” of nitrate pollution.

Studies by the U.S. Geological Survey and others have found that 65 percent of the nitrogen running into the Gulf of Mexico comes from farm fertilizer and livestock manure.

Water Works contends extensive underground drainage systems collect water and send it to drainage ditches that act much like an outlet pipe at a factory. The counties deny that activity is subject to Clean Water Act regulations. “Defendants admit tiling is permanent, deny they are the cause of any issues identified (and) deny they are a proper party to address such issues,” the lawyers wrote.

Agriculture has largely been exempted from the permit requirements set out by the U.S. Clean Water Act, except for large animal confinements. Water Works contend the drainage districts are different, acting much as a sewage treatment plant with an outlet directly into a river, and channeling groundwater, not surface runoff.

The lawyers from Belin McCormick contend Water Works violated court rules by even suggesting the drainage districts had a role in the Gulf pollution that robs oxygen from the water when algae die. The so-called dead zone in the Gulf has what scientists call hypoxia, or low oxygen, from spring to fall.

“Defendants note that this lawsuit does not appear to have been brought by any

entities along the Gulf of Mexico and, therefore, these allegations are irrelevant and violate the notice pleading standards provided in the rules,” the lawyers wrote. “Defendants deny that they have caused or contributed to any eutrophication or hypoxic conditions in the Gulf of Mexico. …”

In another part of the answer, the defendants wrote that they “deny they have contributed to any hypoxia in the Gulf of Mexico, deny they are proper parties to address any such issues in the Gulf of Mexico and are without knowledge or information sufficient to form a belief as to the truth of the causes of issues in the Gulf of Mexico.”

The counties also contended that various federal and state legal statutes bar the Water Works lawsuit and that some of the claims made were caused by “acts of God,” and asked the court to dismiss complaints listed in the case.