DES MOINES, Iowa (AP) — A federal judge has dismissed a Des Moines water utility’s lawsuit against three counties, claiming their agricultural drainage districts have been sending nitrate pollution into the rivers the water utility uses for drinking water.

The judge on Friday dismissed all of Des Moines Water Works’ claims against drainage districts in Sac, Buena Vista and Calhoun counties, ruling that water pollution is an issue for the Iowa legislature to address.

The water utility alleged the three counties that oversee the drainage districts should be required to obtain federal water pollution discharge permits and pay the utility more than $1 million it has spent for increased filtration methods to remove the nitrates from water.

Utility CEO Bill Stowe says the utility’s board will review its options in the case.