A recent decision by a federal appeals court overturned a lower court ruling that would have forced the Environmental Protection Agency (EPA) to determine whether the Clean Water Act (CWA) required the agency to impose federal water quality standards for nitrogen and phosphorus in Iowa and other states in the Mississippi River basin.

The ruling by the 5th Circuit Court of Appeals overturned a Louisiana federal court ruling that had sided with activist groups that want to force the EPA to establish mandatory water quality rules, called total maximum daily loads, or TMDLs. The Iowa Farm Bureau Federation (IFBF) and the American Farm Bureau Federation (AFBF) intervened in case and backed the EPA’s decision to allow states, not the federal government, to determine water quality standards.

That decision was one of...