FLINT, MI - Flint residents dealing with discolored, lead-tainted water were paying the highest water rates in the nation, according to a new study.

A study released Tuesday, Feb. 16, by Washington, D.C.-based Food & Water Watch showed Flint residents were being charged more for water than any other customers in the nation's 500 largest community water systems.

The study, which used information from the Environmental Protection Agency, compared the average annual bill for household using 60,000 gallons of water per year in the 500 most-populated community water systems, according to Food & Water Watch's Public Water for All Campaign Director Mary Grant.

Flint residents paid on average $864 annually for water service. Flint was one of three systems surveyed nationwide charging residents more than $800 annually.

The Westland water system was the second most-expensive major water system in Michigan with an annual bill roughly $300 less than Flint.

The lowest rates nationwide were found in Phoenix, where residents pay less than $85 per year for water service. However, Grant said much of the Phoenix system is subsidized by charging higher rates for water that is used outdoors.

Grant said Flint's ranking was based on rates the city was using when the survey was conducted in January 2015. However, rates have eased slightly after Genesee Circuit Judge Archie Hayman ruled city water customers were entitled to a rate rollback and may be entitled to a rebate for a nine-month period in 2011 and 2012 when rates were illegally increased.

Hayman told the city to eliminate a 35 percent increase in water and sewer rates enacted by Mayor Dayne Walling in 2011 because the hikes violated a city ordinance that required advance notice to customers and that requires such rate increases to be added over 12 months rather than immediately.

City emergency Manager Michael Brown signed off on the 2011 water rate increases and agreed to again raise rates in 2012. Emergency Manager Darnell Earley also called for multiple increases to the city's water rates.

"It's really an indictment of emergency management," Grant said.

However, city officials have said the rate increases were needed to maintain the city's aging infrastructure, which was initially built for a city with twice the population and a thriving manufacturing sector.

The city is in the national spotlight after elevated blood lead levels were discovered in some Flint children after the city changed its water source from Lake Huron water purchased from the Detroit water system to the Flint River in April 2014, a decision made while the city was being run by a state-appointed emergency manager pending the city's joining the Karegnondi Water Authority.

State regulators never required that the river water be treated to make it less corrosive, causing lead from plumbing and pipes to leach into the water supply.

Even though the city reconnected to the Detroit water system in October, local and state officials have warned pregnant women and young children against using the water unless it has been tested because lead levels continue to exceed what can be handled by a filter.

City leaders have said residents are unlikely to see reduced rates by joining the KWA, but rate increases would be less than what was to be expected if the city stayed with Detroit water.

Food & Water Watch, which champions healthy food and clean water for all, has lobbied the city through petitions to stop using the Flint River as its drinking water source and to stop issuing water bills in light of the city's water crisis.

You can view the entire report here.