Washington (CNN) 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, that has lobbied against the Obama rule and whose legal arm previously sued to block it.

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.

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