Kentucky has joined eight other states in challenging a new rule that federal regulators adopted with the goal of protecting water quality.
The states, agriculture groups and others argue the rule goes too far and could subject farmers, homeowners and businesses to burdensome control over activities as simple as digging ditches or building fences.
The lawsuit is part of the controversy over a rule finalized last month by the U.S. Environmental Protection Agency and the U.S. Army Corps of Engineers.
The two agencies have purview over pollution or fill material placed in certain waterways.
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The new rules were needed to clear up questions over jurisdiction to protect streams, wetlands and other areas, said EPA spokeswoman Monica Lee.
U.S. Supreme Court decisions had created uncertainty earlier, Lee said.
"One in three people get drinking water from streams that lacked clear protection" before the new provision, called the Clean Water Rule, Lee said.
But Attorney General Jack Conway and others argue that the federal agencies overreached with the new rule.
The rule would expand the categories of waterways that would or could fall under federal control — including roadside ditches, ponds and some "ephemeral" streams that only flow briefly when it rains, according to a federal lawsuit filed Tuesday by Kentucky and eight other states.
The rule goes far beyond the jurisdiction over "navigable waters" that Congress assigned federal agencies under the Clean Water Act, and usurps states' rights to protect waters entirely within their borders, the lawsuit argues.
The rule could force landowners to navigate bureaucracy and seek permits for everyday activities on their land, Conway said in announcing Kentucky's participation in the federal lawsuit.
"This overly burdensome rule flies in the face of the tradition of environmental regulation, which is to allow states to develop their own responses in how they deal with what's required by the Clean Water Act," Conway, a Democrat running for governor, said in a statement.
The Kentucky Farm Bureau also opposes the new rules, said spokesman Dan Smaldone.
Farmers will face increased regulation because of how the rule defines tributaries and treats ditches, greater uncertainty on how they can work their land, and the potential for lawsuits, Smaldone said.
Kentucky is taking part in the federal challenge with Georgia, West Virginia, Alabama, Florida, Kansas, South Carolina, Utah and Wisconsin.
The complaint was filed in Georgia.
It seeks an injunction barring enforcement of the rule and orders striking it down and requiring the federal agencies to come up with a new draft.
Lee said the agency could not comment on the lawsuit.
However, the agency says on its website that the new rule kept the exemptions for agricultural activities that were in place before, and does not regulate farm ponds, land use or most ditches.
Lee said that before putting the rule in place, the EPA and the Corps of Engineers held more than 400 public meetings and reviewed more than a million comments.
The agencies also relied on scientific studies that show small streams and wetlands play a key role in the health of larger bodies of water downstream.
"America's cherished way of life depends on clean water, " Lee said. "The health of our rivers, lakes, bays, and coastal waters are impacted by the streams and wetlands where they begin."