Story highlights Flint residents paid $864.32 yearly for 60,000 gallons of water in January 2015, group says

But a judge's ruling in August 2015 lowers water bills for Flint residents

"It's completely insane for people to be paying so much who are getting so frankly so little," critic says

(CNN) In early 2015, dirty water in Flint, Michigan, was being tested for lead, two lawsuits were challenging rate increases, and now a study finds residents were then paying the highest water bills of 500 communities surveyed nationwide, according to a nonprofit advocacy group.

Flint was deemed the "most expensive" water provider of the nation's 500 largest community water systems in January 2015, and its residents paid $864.32 yearly for 60,000 gallons of water, the Food & Water Watch group said.

That rate was almost three times national average of $316.20 for government utilities, the group said.

The group advocates publicly owned water systems, which it says provide the most equitable and affordable service, and the group stands up "to corporations that puts profits before people," it says. Flint's water system is publicly owned.

The next highest water provider was the publicly owned service in Bellevue, Washington, where residents paid $855.25 annually, the group said.

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