In an executive order signed Tuesday, President Trump instructed the Environmental Protection Agency to review the Clean Water Rule, a 2015 regulation that gave the agency control over millions of acres of private property.

 “The Clean Water Act says that the EPA can regulate navigable waters, meaning waters that truly affect interstate commerce,” Trump said. “But a few years ago, the EPA decided that navigable waters can mean nearly every puddle or ditch on a farmer’s land, or any place else they decide.”

 The regulation was so broad that it affected farmers, home builders, fertilizer and pesticide makers, manufacturers, golf courses, energy producers and scores of other industries and small businesses that operate on land with a body of water.

 The EPA also came under fire for its efforts to promote the controversial regulation; its social-media campaign violated a federal prohibition on using taxpayer money to lobby the public, the Government Accountability Office concluded in late 2015.

 That same year, a total of 27 states filed a lawsuit challenging the EPA over the Clean Water Rule, which is also known as Waters of the United States or WOTUS. The regulation “is currently on hold, blocked by the Court of Appeals for the 6th Circuit due to litigation against it,” the Hill reported.

 But Trump’s executive order “will have almost no immediate legal effect,” the New York Times reported, noting it’s difficult to claw back a rule that’s already underway. The article continued:

The order will essentially give Mr. Trump a megaphone to direct his new Environmental Protection Agency administrator, Scott Pruitt, to begin the complicated legal process of rewriting the sweeping 2015 rule known as Waters of the United States. But that effort could take longer than a single presidential term, legal experts said.

… Because both of those rules were finalized under existing laws long before Mr. Obama left office, they cannot be simply undone with a stroke of the president’s pen, legal experts in both the Obama and Trump White Houses have said.

… To follow the law, Mr. Pruitt will have to withdraw the current Obama administration water regulation and craft a new version of the rule, along with a justification as to why it would be legally superior to the earlier one. That would be subject to a public comment period before it is finalized, and it could face new lawsuits afterward.

 But even as a symbolic move, the executive order signals the Trump administration’s attempt to roll back EPA overreach.