The US Environmental Protection Agency unveiled expanded safeguards Wednesday for streams and wetlands that supply drinking water to more than 100 million people.

The EPA said it had finalized rules to better ensure that US water protection is "precisely defined and predictably determined."

Approximately 117 million Americans, or one in three people, use water from sources that lacked clear protection before the implementation of the new measures, the EPA said.

"Protection for many of the nation's streams and wetlands has been confusing, complex and time-consuming," the EPA said in a statement.

The agency worked with the US Army to finalize the new rules, which fall under the framework of the US Clean Water Act that dates to 1972.

"For the water in the rivers and lakes in our communities that flow to our drinking water to be clean, the streams and wetlands that feed them need to be clean too," said EPA Administrator Gina McCarthy.

"Protecting our water sources is a critical component of adapting to climate change impacts like drought, sea level rise, stronger storms, and warmer temperatures," she said.

The new Clean Water Rule was finalized "to protect these important waters, so we can strengthen our economy and provide certainty to American businesses," she said.

But the new measures are creating an uproar in rural areas and among Republicans in Congress.

"The rule is written so broadly it could allow the EPA to regulate virtually every body of water in the United States, including private and public lakes, ponds and streams," said a statement put out by the office of Congressman Lamar Smith, chairman of the House Science, Space and Technology Committee. "The rule expands the EPA's jurisdiction, giving the agency the power to restrict Americans from making decisions about their own property," Smith said.

The EPA said it created the rule after receiving requests for clarification from Congress, agriculture, environmental groups and other entities over the course of more than a decade.

The agency added that the rule was created after reviewing a report that brought together more than 1,200 studies on how small streams and wetlands play a major role in the health of larger bodies of water.