LANSING, Mich. — The State of Michigan sued Flint Wednesday, alleging that the City Council’s refusal to approve a broadly backed deal to buy water over the long term from a Detroit-area system is endangering public health — following a crisis that has largely been blamed on the state itself.
The Department of Environmental Quality had threatened legal action if the council did not approve Mayor Karen Weaver’s recommendation or propose a reasonable alternative by Monday. The council instead OK’d a short-term extension of its contract with the Detroit authority.
‘‘Ensuring that the residents of Flint have drinking water that meets public health standards is our primary concern,’’ the DEQ’s director, Heidi Grether, told The Associated Press in a phone interview.
‘‘The city council’s inaction does not give us security that that is going to be the case.’’
State and federal officials do not want Flint to change water sources a third time after a fateful 2014 switch resulted in lead contamination, while the city was under state management.
The lawsuit says Flint has no other currently available water source and is at risk of incurring $1.8 million in extra costs over the next three months. It seeks an order barring Flint from switching again and requiring it to enter the 30-year contract to comply with federal and state laws.
In April, Weaver recommended that the city of nearly 100,000 residents continue getting its water from the Detroit-area Great Lakes Water Authority long term, saying another switch would be too risky and expensive. Her decision is supported by top federal, state, and county officials, but has drawn concerns from council members.
The agreement negotiated by Weaver ‘‘is the only option that will be protective of public health in Flint, ensure the future financial violability of Flint’s water fund, and promote investment in Flint’s water distribution system,’’ the suit says.
Messages seeking comment were left with council members. At a meeting Monday, at least one expressed distrust over ‘‘countless bad decisions by the state government,’’ according to The Flint Journal, while another said the council did not yet have enough information.
Weaver said she is disappointed by the suit but not surprised — given the previous warning — ‘‘that the state and federal government are now involved in making a decision we as city leaders should be making for Flint.’’
Under her plan, Flint would remain a customer of the Great Lakes Water Authority for the next 30 years instead of transitioning to a Flint-area pipeline. A previous money-saving decision to join the Karegnondi Water Authority set the stage for the disaster when state-appointed financial managers controlling Flint in 2014 decided to temporarily tap the Flint River while the regional pipeline to Lake Huron was being built.
The river water was not treated to reduce corrosion for 18 months. As a result, lead leached from old pipes and fixtures, causing elevated lead levels in children and leaving residents to drink and bathe with bottled or filtered water.
Experts suspect that a deadly Legionnaires’ disease outbreak was tied to the water.
Flint returned to the Great Lakes Water Authority, which services much of Detroit and the suburbs, in 2015.
The suit is just the latest legal filing stemming from a disaster that has led 15 current or former government officials to be charged with crimes — many of them state employees, including two members of Republican Governor Rick Snyder’s cabinet.
Five officials, including the state Health and Human Services director, Nick Lyon, face involuntary manslaughter charges.
Numerous residents have sued seeking damages, and a federal judge has separately approved a landmark deal to replace water lines at 18,000 homes.
Weaver said that staying with the Detroit system and using the local county as a backup would avoid a 40 percent increase in already-high water rates.
Flint has estimated it would save at least $58 million by not having to upgrade its own troubled water plant to treat water coming from the new pipeline.
The savings could go toward a $177 million update of the city’s deteriorated distribution system, including fixing leaky water mains and replacing lead service pipes.
‘‘The people of Flint have waited long enough for a reliable, permanent water source,’’ Weaver said in a prepared statement.
‘‘Implementing my recommendation will provide that, and will allow us to move forward as a community and focus more on rebuilding our city.’’