The Supreme Court's conservative majority ruled for San Francisco in limiting the power of environmental regulators to prevent ocean discharges of polluted stormwater.

The Supreme Court ruled Tuesday that the Environmental Protection Agency overstepped its authority under the Clean Water Act by imposing unclear water quality standards on San Francisco, siding with the city in its appeal of a lower court ruling.

The Supreme Court has made it harder for environmental regulators to limit water pollution, ruling for San Francisco in a case about the discharge of raw sewage that sometimes occurs during heavy rains.

The Supreme Court on Tuesday struck down rules regulating the discharge of water pollution, narrowing the landmark Clean Water Act in an unusual case that featured sewage and an effort by one of the nation’s greenest cities to take on the Environmental Protection Agency.

The Supreme Court on Tuesday ruled that EPA cannot enforce requirements in wastewater permits that “do not spell out what a permittee must do or refrain from doing,” in a major blow to the agency’s power under the Clean Water Act.

The conservative Supreme Court aligned with liberal San Francisco on Tuesday, ruling that federal environmental regulators overstepped their authority by attempting to impose vague limits on how much raw sewage the California city may pump into the Pacific Ocean.