The Biden administration is taking a step towards reversing Trump-era rollbacks to water regulations, proposing a rule to restore the pre-Obama definition that outlines which waters it will seek to protect from pollution.

In a press release, the Environmental Protection Agency (EPA) said that it, alongside the Army Corps of Engineers, proposed returning to the pre-Obama definition of what constitutes a "Water of the United States."

These waters are those that get protections under the Clean Water Act, which makes it illegal to release pollutants into them without permits, which can set limits and specifications on how much pollution is allowed into the bodies of water.

The new proposal notes that the department was already using the pre-Obama interpretation after a judge in August vacated the Trump-era rule. But it argues that completing the proposal is "vital" because the Trump rule could return based on developments in the litigation.

The administration previously announced its intent to return to the protections that were in place for decades in July, saying it would take a two-track approach that first restores pre-Obama water regulations and then later put forward a new definition.

Last year, the Trump administration put forward a rule that both undermined Obama-era protections and also rolled back some pre-Obama ones, including for wetlands, that had been in place for decades. 

If finalized, this new proposal would return the pre-Obama protections at which the Trump administration took aim.

It argues that the Trump rule is "inconsistent" with the objectives of the Clean Water Act.  

In 2015, the Obama administration expanded which waterways are protected, including by adding protections for waters near rivers and lakes because of studies showing they can impact larger bodies. 

EPA Administrator Michael Regan has said he doesn't plan to restore the Obama-era regulations "verbatim," and will look for a rule that addresses concerns from both environmentalists and the agricultural industry. 

“In recent years, the only constant with WOTUS has been change, creating a whiplash in how to best protect our waters in communities across America,” Regan said in a statement on Thursday.

“Through our engagement with stakeholders across the country, we’ve heard overwhelming calls for a durable definition of WOTUS that protects the environment and that is grounded in the experience of those who steward our waters. Today’s action advances our process toward a stronger rule that achieves our shared priorities,” he added.

The EPA's move received pushback from Republicans. The top GOP member of the Senate Environment and Public Works Committee, Shelley Moore Capito (W.Va) expressed fear that the agency could ultimately go further than the Obama administration in its second phase, and said that the current proposal could face court challenges.

"Based on the indications of today’s first step, the Biden EPA’s final rule will most likely be challenged in the courts, and thus the cycle of uncertainty continues,” she said in a statement.