The EPA's regulation of Concentrated Animal Feeding Operations (CAFO) dates to the 1970s. In February 2003 new rules were adopted that amended the 1972 Clean Water Act, and tightened the manure disposal and management requirements for animal feeding operations.
The new regulations have limitations on land application of manure and wastewater; increased accountability, recordkeeping and inspection requirements; and a sliding scale of provisions depending on the number of animal units being housed.
Because states have jurisdiction over the federal rules, further detail should be obtained from your state environmental agency, Cooperative Extension program, or livestock association.
Information on the EPA regulations is available at
http://cfpub.epa.gov/npdes/afo/cafofinalrule.cfm
