WASHINGTON — The Trump administration last week announced the repeal of a major Obama-era clean water regulation that had placed limits on polluting chemicals that could be used near streams, wetlands and other bodies of water.

The rollback of the 2015 measure, known as the Waters of the United States rule, adds to a lengthy list of environmental rules that the administration has worked to weaken or undo over the past 2 1/2 years. Those efforts have focused heavily on eliminating restrictions on fossil fuel pollution, including coal-fired power plants, automobile tailpipes, and oil and gas leaks, but have also touched on asbestos and pesticides.

An immediate effect of the repeal is that companies will no longer need a permit to discharge potentially harmful substances into many streams and wetlands. But the measure, which is expected to take effect in a matter of weeks, has implications far beyond the pollution that will now be allowed to flow freely into waterways.

The Obama administration implemented the rule in response to a Supreme Court ruling that opened the door to a more expansive legal definition of “waters of the United States” under the 1972 Clean Water Act. With last week’s announcement, the Environmental Protection Agency is aiming to drastically narrow that definition, a move that could be difficult for future administrations to undo.

Patrick Parenteau, a professor of environmental law at the University of Vermont, said that for conservative states and leaders who hold the view that the Clean Water Act has been burdensome for farmers and industry, “this is an opportunity to really drive a stake through the heart of federal water protection.”

Overhauling the rule had been a central campaign pledge for President Donald Trump, who characterized it as federal over-reach that impinged on the rights of farmers, rural landowners and real estate developers to use their properties as they see fit. Trump signed an executive order in the early days of his administration directing federal agencies to begin the work of repealing and replacing it.

“Today’s final rule puts an end to an egregious power-grab,” Andrew Wheeler, the administrator of the EPA, said when announcing  the repeal.

Wheeler said the rollback would mean “farmers, property owners and businesses will spend less time and money determining whether they need a federal permit and more time building infrastructure.”

Agricultural groups, an important political constituency for Trump, praised the repeal. Zippy Duvall, president of the American Farm Bureau Federation, said the water rule had sparked outrage from thousands of farmers and ranchers across the country and led to the largest effort to kill a regulation in his organization’s history.

“When you take private property rights from a man who’s worked all his life,” Duvall said, “that is very intrusive to him and it’s something he just can’t stand for.”

But environmentalists assailed the move. “With many of our cities and towns living with unsafe drinking water, now is not the time to cut back on clean water enforcement,” said Laura Rubin, director of the Healing Our Waters-Great Lakes Coalition.

The Obama rule was designed to limit pollution in about 60% of the nation’s bodies of water, protecting sources of drinking water for about one-third of the United States. It extended existing federal authority to limit pollution in large bodies of water, like the Chesapeake Bay and Puget Sound, to smaller bodies that drain into them, such as tributaries, streams and wetlands.

Under the rule, farmers using land near streams and wetlands were restricted from doing certain kinds of plowing and from planting certain crops, and would have been required to obtain EPA permits to use chemical pesticides and fertilizers that could have run off into those bodies of water. Those restrictions will now be lifted.

The Environmental Protection Agency and the Army Corps of Engineers, which had worked together to write the original Obama rule, are expected to issue a new, looser replacement rule by the end of this year. It is expected that the new rule, still being developed, will retain federal protections for larger bodies of water, the rivers that drain into them and wetlands that are directly adjacent to those bodies of water.

But it will quite likely strip away protections of so-called ephemeral streams, in which water runs only during or after rainfalls, and of wetlands that are not adjacent to major bodies of water or connected to such bodies of water by a surface channel of water. Those changes would represent a victory for farmers and rural landowners who lobbied the Trump administration aggressively to make them.

Lawyers said the interim period between the completion of the legal repeal of the Obama rule and the implementation of the new Trump rule this year could be one of regulatory confusion for farmers and landowners, however.

“The Obama clean water rule had very clear lines defining which waters are protected by the Clean Water Act, versus which waters are not, while repealing the rule means replacing those lines with case-by-case calls,” said Blan Holman, an expert on water regulations with the Southern Environmental Law Center.

Holman said the administration was replacing “clear, bright-line rules” with a case-by-case system. “This will be very unpredictable,” he said.

What's your reaction?