On July 29, 2015, the Minnesota Supreme Court held that a farm using fields as cropland in the summer and as an animal feeding site during the winter need not obtain a National Pollution Disposal Elimination System (NPDES) permit but must nonetheless obtain a state disposal system (SDS) permit. In re Reichmann Land & Cattle, LLP, A13-1461, (Minn. July 29, 2015). The Pope County, Minnesota, farm at issue uses a portion of its cropland as a winter feeding facility for cattle. Following the fall harvest, the farm places cattle on the lot, which consumes crop residues through the winter. In the spring, the farm moves the cattle off the lot and plants new crops for the growing season.

The Clean Water Act and EPA regulations require an NPDES permit for discharges from animal feeding operations (AFOs), which are facilities where at least 1,000 cattle are kept on the lot for more than 45 days in a 12–month period, and where “[c]rops, vegetation, forage growth, or post-harvest residues are not sustained in the normal growing season over any portion of the lot.” 40 C.F.R. § 122.23(b)(1). MPCA argued that the phrase “sustained in the normal growing season” should take into account the period during which the animals are present, and that because crops are “not sustained” on the Pope County farm through the winter, therefore the facility was an AFO and required an NPDES permit. Moreover, MPCA claimed the Court should defer to its interpretation of this phrase, in accordance with In re Cities of Annandale & Maple Lake NPDES/SDS Permit Issuance for the Discharge of Treated Wastewater, 731 N.W.2d 502 (Minn. 2007).

The Court disagreed, holding that Annandale does not require deference to an agency’s interpretation of a regulation where the language is unambiguous. In this case, the Court found the regulation was unambiguous—if crops are sustained on the lot during the “normal growing season” (which in this case they were), then under the plain language of section 122.23(b)(1), the lot is not an AFO.   However, the Court determined that the farm would require an SDS permit because, under MPCA rules, it met the definition of an “animal feeding facility” and did not qualify for the “pasture exemption” under Minn. Stat. § 116.07, subd. 7d (which the Court held required a vegetative ground cover during the entire growing season, even during the very early part of the season, when crops were being planted).