County brought action against Montana Department of Environmental Quality (DEQ), seeking declarations that it lacked authority to perform acts required by administrative rule governing minimum control measures for municipal storm sewer systems and that those requirements constituted unfunded mandate.
The District Court granted DEQ’s motion for summary judgment, and county appealed.
The Supreme Court held that:
- County’s prior applications for permits to discharge storm water did not independently establish its authority to enact and enforce third-party regulatory mechanisms;
- County had statutory authority to develop, implement, and enforce storm water management program; and
- County’s obligation to implement minimum control measures did not constitute prohibited unfunded mandate under state law.