DETROIT (AP) -- Flint must take several steps before switching its drinking water source again due to the lead-contamination crisis, federal officials said Friday, including a three-month water-testing period.
The U.S. Environmental Protection Agency updated its order issued in January, calling for Flint to complete a three-mile interconnection so it can test water from the new source for three months while continuing to provide water from Detroit's system. The city also must submit a new water treatment plan.
Flint is expected to switch to the Karegnondi Water Authority late next year and treat the water itself. The Associated Press sent an email seeking comment from Flint officials.
The city switched from Detroit water to the Flint River in 2014 to save money, but corrosive water caused lead, a neurotoxin, to leach from aging pipes into homes. Doctors have detected elevated levels of lead in hundreds of children.
The city has since returned to Detroit's system as it awaits completion of the Karegnondi pipeline. And while the city's water system heals from the contamination, Flint residents are urged to use bottled water or filtered tap water.
"Given the harmful effects of the source water switch in April of 2014, it is critical that any future changes in source water for the city be properly planned," Robert Kaplan, the EPA's acting regional administrator, wrote in a letter this week to Flint Mayor Karen Weaver and Michigan Gov. Rick Snyder.
Kaplan's predecessor, Susan Hedman, stepped down Feb. 1 amid criticism that the agency failed to act sooner to address lead contamination in the predominantly African-American city. She denied wrongdoing but said she wanted to avoid becoming a distraction.
Michigan officials declared a public health emergency in October 2015, and the EPA declared an emergency three months later.
Federal, state and local officials have argued over who is to blame.
An EPA inspector general's report concluded last month the federal agency should have acted sooner. A panel appointed by Michigan Gov. Rick Snyder found earlier the state is "fundamentally accountable" for the lead crisis because of decisions made by state environmental regulators and state-appointed emergency managers who controlled the city.
Officials say lead levels in Flint's water have been improving. As of September, 95 percent of samples are at or below the designated action level of 15 parts per billion and further decreases are expected when the next round of results are released early next year.