By Timothy Gardner

WASHINGTON The Biden administration on Tuesday weakened a rule regulating pollution of waterways to conform with a ruling by the U.S. Supreme Court that limited the regulatory reach of the Environmental Protection Agency.

The court in May decided 9-0 to overturn a lower court's ruling against a couple in Idaho, Chantell and Michael Sackett, that had upheld the EPA's determination that their property near a lake contained wetlands protected by the Clean Water Act of 1972.

President Joe Biden has argued that the ruling upended the legal framework used for decades to fight water pollution and pledged to use every legal power his administration has to protect waters from pollution.

The EPA and the U.S. Department of the Army Corps of Engineers issued a final rule on Tuesday amending a standard it issued in January that revised the definition of which water bodies constituted "waters of the United States" under the 1972 Clean Water Act.

Under the January revision, the waters included traditional navigable waters, impoundments of qualifying waters, tributaries to qualifying waters and wetlands adjacent to qualifying waters.

Many farmers and landowners had slammed the broad interpretation, saying the EPA had overreached its powers.

The EPA administrator Michael Regan said he was "disappointed" by the Supreme Court's decision but that the administration had an obligation to apply the decision alongside co-regulators in state and tribes.

The EPA said the new amendments were limited and changed only parts of the 2023 rule that were invalid under the Sackett decision.

The final rule, for example, removed a standard called the "significant nexus test" from consideration when identifying tributaries and other waters as federally protected. The standard was meant to identify waters that significantly affect the chemical or biological integrity of traditional navigable waters and interstate waters.

Madeleine Foote, deputy legislative director for the League of Conservation Voters nonprofit group, said the court's decision leaves critical wetlands and other waters open to pollution and destruction and urged Congress to boost clean water protections.

The administration was forced to tweak the rule to reflect the court's "disregard of science, the law, and basic commonsense to put the profits of polluters ahead of the health of our communities," especially communities of color, Foote said.

(Reporting by Timothy Gardner; Editing by Marguerita Choy)