KEWAUNEE, Wis. (AP) — One of Wisconsin’s largest dairy farms is suing the Wisconsin Department of Natural Resources over changes to its wastewater permit that require the operators to limit the size of their herd and begin monitoring groundwater in an area where nitrate contamination has occurred.

Kinnard Farms in Kewaunee County says in its complaint that the business will be harmed if it isn’t allowed to expand its herd and will be burdened by the cost of a groundwater monitoring system.

The Kinnard operation includes 16 industrial farms with about 8,000 cows. It has struggled with agricultural pollution for years as contaminants began showing up in private wells.

Back in March, the DNR announced the farm is required to conduct water testing.