The U.S. Environmental Protection Agency (EPA), under the direction of the Trump administration, will revoke a rule that gives the agency broad authority over regulating the pollution of tributaries and wetlands that flow into the country’s largest rivers. 
EPA Administrator Scott Pruitt told Congress on June 27, 2017, that the agency would “provide clarity” by “withdrawing” the rule, and follow standards set in 2008. Pruitt had previously said he would recuse himself from working on litigation to the rule.
“We are taking significant action to return power to the states and provide regulatory certainty to our nation’s farmers and businesses.”
During his testimony, Pruitt told senators that the Obama-era rule:
“… created a situation where farmers and ranchers, landowners across the country did not know whether their stream or dry creek bed, in some instances, was actually subject … to EPA jurisdiction and EPA authority.”
He added that:
“… they were facing fines that were substantial as they engaged in earth work to build subdivisions – I mean, it was something that created a substantial amount of uncertainty and confusion.” 
The Clean Waters Act was last updated in 2015 to define waterways – including streams, rivers, and other bodies – the federal government can regulate, thus expanding protection for 2 million miles of streams and 20 acres of wetlands, and drawing the ire of the agriculture and energy industries.
That year, the rule was delayed by a federal appeals court, after 13 states filed a lawsuit against the EPA and the Army Corps of Engineers. It remains on hold while the case works its way through the courts.
In February 2017, President Trump said during the signing of an executive order calling for a review of the Clean Waters Act that it should apply only to navigable waters that impact interstate commerce. The decision would put at risk the drinking water sources of 1 in 3 Americans.  
Environmental groups say rolling back the rule will put the Midwestern Great Lakes region at risk, and lead to pollution in some of the nation’s most sensitive wetland areas.
Howard Learner, executive director of the Environmental Law & Policy Center, said:
“This foolish rollback of clean water standards rejects years of work building stakeholder input and scientific data support, and it imperils the progress for safe clean drinking water in the Midwest.” 
Kierán Suckling, executive director at the Center for Biological Diversity, added:
“Revoking the clean water rule will open the door to the pollution and bulldozing of some of America’s most important wetlands.”
So far, the Trump administration has received an astounding 500,000 comments, including numerous requests to preserve the existing regulation.
Following the public comment period, and after reaching a final decision, the EPA will have to author its own proposed rule for designing which waters should be federally protected under the 1972 law.
Environmental and conservation groups have vowed to fight the repeal.
Michael Brune, executive director of Sierra Club, said in a statement:
“It goes without saying that the Trump administration doesn’t care about the environment, public health, or its duty to protect our most precious natural resources — and that is why it’s up to us, the American people, to hold them accountable. We will fight this and every other attempt by polluters and the Trump administration to destroy our water resources.” 
 Think Progress