A federal appeals court has blocked an Army Corps of Engineers-Environmental Protection Agency rule that aimed to clear up the murky definition of which bodies of water fall under federal regulation.

The Oct. 9 decision from the U.S. Court of Appeals for the Sixth Circuit didn’t strike down the regulation but bars it from taking effect nationwide, pending further court action.

The rule, which EPA and the Corps announced on May 27, is important to construction firms because it determines the situations in which contractors must get a federal permit for building in and around wetlands and streams.

Larry Liebesman, a senior advisor at Dawson & Associates, Washington, D.C., says, “It creates a tremendous time period of uncertainty, I would say, because everything is going back back to the status quo.” That would mean working under regulatory guidance from the 2000-2008 period

Liebesman, formerly a senior trial attorney with the Justice Dept.’s Environmental Division, adds, “Folks that are operating are going to be dealing with that until there's a decision on the merits of whether this rule is valid or not. And that could take a long period of time, because the administrative record is huge.”

A different federal court in August had issued a preliminary injunction against the rule, but only in 13 states. The regulation took effect on Aug. 28 in all the other states.

The EPA-Corps rule seeks to clear up what the Clean Water Act meant by "waters of the United States" and thus fall under federal jurisdiction.

The 2-1 decision by a three-judge panel of the appellate court said the states that sought the stay “have demonstrated a substantial possibility of success on the merits of their claims.” Among other things, the states contend that the rule doesn’t follow a 2006 U.S. Supreme Court decision on wetlands regulation.

The appellate court also pointed to the regulation's provision specifying certain distances to determine whether water bodies are “adjacent” to federal waters. The court said that “the rulemaking process by which the distance limitations were adopted is facially suspect.” The case is State of Ohio v. U.S. Army Corps of Engineers.

Tom Woods, National Association of Home Builders chairman, praised the court's action. Woods said in a statement that the regulation “raises housing costs, tramples states’ rights and adds unnecessary regulatory burdens to small businesses.”

Jon Devine, senior attorney in the Natural Resources Defense Council’s water program, said that the ruling “is disappointing but not a surprise.” He added, “We look forward to making the case in court about the critical public interests at stake.”