The Bush administration has sought to delay a Clinton administration regulation designed to clean up over 20,000 polluted rivers, lakes and other bodies of water in the United States.
The Environmental Protection Agency (EPA) asked a US District Court to defer for 18 months a legal challenge to a clean water regulation to give the agency time to review the revisit the rule.
The EPA said the year-and-a-half stay would enable it to review and revise the rule to achieve a programme that is workable and meets the goal of clean water.
"I am asking for this additional time to listen carefully to all parties with a stake in restoring America's waters . . . to find a better way to finish the important job of cleaning our great rivers, lakes and streams," EPA Administrator Ms Christine Todd Whitman said in a statement.
The EPA said it turned to the federal court because of the ongoing controversy surrounding the rule, published in July 2000, and in light of a recent study by the National Academy of Sciences.
The study, released in June, agreed water pollution was a serious problem but recommended a more science-based approach to assure the right bodies of water were selected for cleanup.
The conservationist group Earthjustice called the move a backdoor tactic for targeting environmental protections.
"The only thing dirtier than our nation's polluted waters is the Bush administration's backdoor attempt to weaken the Clean Water Act," said Earthjustice attorney Mr Howard Fox. "This is another example of the Bush administration's approach of rolling back our environmental and public health protections."