The U.S. Environmental Protection Agency on Wednesday issued rules it said will protect drinking water for 117 million Americans by protecting small streams, tributaries and wetlands from pollution and development, the Associated Press reported.

EPA and the U.S. Army Corps of Engineers sought to clarify which smaller waterways fall under federal protection. Two Supreme Court rulings had left the reach of the Clean Water Act uncertain.

EPA Administrator Gina McCarthy said the rule will only affect waters that have a “direct and significant” connection to larger bodies of water downstream that are already protected. The EPA has said 60 percent of the nation’s streams and waterways are vulnerable, and these rules clarify which of those waters are protected. The regulations would only kick in if a business or landowner does something that threatens the waters.

President Barack Obama said in a statement that the rule “will provide the clarity and certainty businesses and industry need about which waters are protected by the Clean Water Act, and it will ensure polluters who knowingly threaten our waters can be held accountable.”

The rules have already run into deep opposition from farm groups and the Republican-led Congress. The House voted to block the regulations earlier this month, and a similar effort is underway in the Senate.

Echoing the concerns of farm groups, lawmakers have said the rules could greatly expand the reach of the clean water law and create confusion among officials in the field as to which bodies of water must be protected. Farmers wary of more federal regulations are concerned that small bodies of water on their private land could now be subject to federal oversight.

After the rule was released, Republican Sen. James Inhofe of Oklahoma, chairman of the Senate Environment and Public Works Committee, said his panel will consider the Senate bill to force the EPA to withdraw and rewrite the rules this summer and “continue our work to halt EPA’s unprecedented land grab.”

McCarthy said the regulations don’t create any new permitting requirements for agriculture and even adds some new exemptions for artificial lakes and ponds and water-filled depressions, among other features.

These efforts were “to make clear our goal is to stay out of agriculture’s way,” McCarthy said in a blog on the EPA website. Read more