A livestock feeding operation can be a concentrated animal feeding operation (CAFO) based on 1) size (1,000 animal units or larger), 2) size and management or location (300 to 999 animal units with a direct discharge to a water of the United States or a water of the U.S. running through the operation), or 3) designation as a CAFO due to a significant contribution of manure or process wastewater to waters of the U.S.