The Environmental Protection Agency is set Thursday to announce the repeal of the Obama-era Waters of the United States rule that extended federal authority and protections to streams and wetlands, according to a source familiar with the details of the announcement.
The announcement is scheduled to take place at the National Association of Manufacturers, a trade group in Washington, DC.
The 2015 regulation, commonly known as WOTUS, defined what bodies of water are protected under the federal Clean Water Act but was a favorite punching bag of Republicans, who ridicule it as government overreach. Democrats defended it as necessary to ensure waterways remained pollution-free.
Thursday's repeal of the regulation is likely to draw intense litigation from the environmental community. Those groups have argued the Trump EPA's changes to the rule protects fewer small waterways and that could result in more pollution and put people at risk.
A source who's been invited to the announcement tells CNN that EPA administrator Andrew Wheeler is expected to sign the finalized rule repealing the regulation.
"It's the first of two steps. First the regulation has to be repealed then the EPA will move to replace it with a new regulation," the source said. Wheeler unveiled a proposed replacement regulation last December.
The EPA announced Wednesday that Wheeler will "make a major water policy announcement" but did not specify what the announcement would be. EPA and the Army Corps of Engineers did not immediately respond to CNN's request for comment.
President Donald Trump has repeatedly called clean water a priority for his administration. "We want crystal clean water and that's what we're doing and that's what we're working on so hard," he said in an environmental speech earlier this summer.
But the Obama-era rule has been under attack from Trump and conservatives for years.
Several states challenged the Obama-era rule, and a federal judge in Georgia ruled in favor of their challenge last month.
EPA has said in the past it seeks to repeal and replace WOTUS for economic and regulatory certainty reasons.
In December Wheeler said the change "will result in significant cost savings" while protecting the nation's waterways and reducing "barriers to important economic and environmental projects."
The proposed replacement would divide US waters into six categories: traditional navigable waters, tributaries to those navigable waters, certain ditches -- including those used for navigation or affected by the tide, certain lakes and ponds, impoundments and wetlands that are adjacent to water covered by the rule.
It would exclude groundwater; ditches, including roadside and farm ditches; prior converted cropland; stormwater control features and wastewater and waste treatment systems.