DES MOINES, Iowa (AP) – A group opposed to a lawsuit filed by Des Moines Water Works says the utility company’s bill of $40,000 for water quality studies and other records that the group has requested is unprecedented. The utility company says the bill is a “good-faith estimate” for the extensive effort required to meet the Iowa Partnership for Clean Water’s request, part of which includes records dating back to 1974.

Des Moines Water Works filed a lawsuit against Calhoun, Buena Vista and Sac counties in March, claiming draining districts in the counties are funneling nitrates from farm fields into the Raccoon River. The river is a drinking source for 500,000 residents.

The Des Moines Register reports the group claims the utility company has pushed to seal court documents pertaining to the case and is purposely delaying fulfilling the records request.