WEST PALM BEACH -- A federal judge ruled Friday that the state's practice of back-pumping polluted water into Lake Okeechobee without a permit violates the U.S. Clean Water Act.

U.S. District Judge Cecilia M. Altonaga ordered the South Florida Water Management District to apply for permits "forthwith" but did not set a deadline, most likely because even the judge acknowledged in a December finding that there was no quick fix to the decades-old practice.

The ruling has no real teeth because it does not preclude the state from back-pumping water into the lake tomorrow should the need arise. A permit request would eventually go through the state Department of Environmental Protection.

"If and when we're asked, we'd be happy to evaluate that request to make the best decisions as to whether or not back-pumping should take place," said DEP spokeswoman Sarah Williams.

Since the 1970s, Florida water managers have pumped water from canals carrying pollutants from adjacent sugar-growing lands and cities into the lake for flood control and to bolster water reserves that could be used during drought.

Water managers say the method is crucial to keep cities from being inundated and that a lengthy permitting process would only serve to slow Everglades restoration and could put the state's entire flood control system in jeopardy. The district will likely appeal the judge's ruling.

With South Florida suffering from an unprecedented drought, the district as recently as Thursday heard proposals to begin back-pumping into the lake to help farmers who have seen millions of dollars in losses because of water restrictions.

Several groups, including the Miccosukee Tribe of Indians, which considers the lake and the Everglades part of its ancestral home, sued the district, claiming that back-pumping of polluted water into the lake was putting Everglades restoration in jeopardy.

The groups also claimed the polluted water contains harmful nitrogen which creates toxic algae blooms and byproducts that can be dangerous to humans. Lake Okeechobee serves as a backup drinking water supply for millions in South Florida. At 730 square miles, it is the second-largest freshwater lake in the continental U.S.

"Plaintiffs have met their burden of showing the potential for irreparable harm," Altonaga wrote in Friday's ruling.

The district "has consistently and energetically resisted obtaining the permits the Clean Water Act requires for these Lake Okeechobee pumps," said Miccosukee attorney Dion Carroll. "This is a big victory for a beautiful Lake that has waited far too long for clean water."

David Guest, lead attorney for Earthjustice which helped argue the case on behalf of the plaintiffs, applauded the ruling, noting it gave merit to the claim that "there's a human health risk at play here."

"The water management district has been acting like back-pumping is just fine, and they now have a judgment against them saying they are required to change their ways," Guest said, adding that the district should find other places to store water for agriculture and flood control.

In January, the U.S. Environmental Protection Agency said it may seek an amendment to the Clean Water Act, arguing that the Florida case and others have created confusion over when and where permits are required. Some judges are interpreting the law in a manner Congress never intended, the EPA contends.

"We stand ready to work with Congress if Congress chooses to amend the Clean Water Act to clarify when a permit is needed and when it isn't," Benjamin Grumbles, EPA's assistant administrator for water, said then in an interview with The Associated Press.

EPA spokesman Dale Kemery said Friday the agency was still working toward clarification, but noted the "glacial pace at which Congress moves."

"We will continue to manage our waters in the public's interest and remain committed to protecting our natural resources, our economy and the health, welfare and safety of Florida's communities," the district said in a statement.