Michigan officials have announced that lead levels of the Flint water supply have finally fallen below federal limits, but still advised residents to keep using bottled water and filters as a precaution.

The Department of Environmental Quality had measured the city’s lead levels over the last six months to be 12 parts per billion, putting it below the federal “action level” of 15 ppb. Lead levels were 20 parts per billion in the period January to June 2016. Officials told the Associated Press the current level is similar to that of other American cities.

The city has been dealing with this public health crisis since April 2014. During that time, 12 people died of Legionnaire’s disease linked to the contaminated water and several children were diagnosed with lead poisoning.

In pictures: Flint water crisis Show all 10 1 /10 In pictures: Flint water crisis In pictures: Flint water crisis Anthony Fordham picks up bottled water from the Food Bank of Eastern Michigan to deliver to a school after elevated lead levels were found in the city's water in Flint Reuters In pictures: Flint water crisis Michigan National Guard Staff Sergeant William Phillips (L) assists a Flint resident with bottled water at a fire station in Flint Reuters In pictures: Flint water crisis Flint residents Arthur Woodson, left, and Tony Palladino Jr. protest the arrival of Flint native and filmmaker Michael Moore as Moore accuses Gov.Rick Snyder of poisoning Flint water during a rally outside of city hall in Flint AP In pictures: Flint water crisis Flint residents pick up bottled water and water filters at a fire station in Flint. Michigan National Guard members were set to arrive in Flint to join door-to-door efforts to distribute bottled water and other supplies to residents coping with the city's crisis over lead-contaminated drinking water Reuters In pictures: Flint water crisis Soldiers from the Michigan Army National Guard Flint prepare to give Flint residents bottled water at a fire station in Flint Getty Images In pictures: Flint water crisis Justin Roberson (L), age 6, of Flint, Michigan and Mychal Adams, age 1, of Flint wait on a stack of bottled water at a rally where the Rev. Jesse Jackson was speaking about about the water crises at the Heavenly Host Baptist Church in Flint Getty Images In pictures: Flint water crisis A man sits next to a stack of bottled water at the Heavenly Host Baptist Church in Flint 2016 Getty Images In pictures: Flint water crisis The top of a water tower is seen at the Flint Water Plant. President Barack Obama declared a state of emergency in Michigan and ordered federal aid to be used to help state and local response efforts to an area affected by contaminated water Reuters In pictures: Flint water crisis Rosie Wright, center, rallies with the crowd over Flint's water crisis in Ann Arbor, Michigan AP In pictures: Flint water crisis Rick Catherman participates in a rally around Flint's water crisis in Ann Arbor, Michigan AP

The state of Michigan acknowledged the problem in October 2015, saying that certain phosphates were not added to the pipes in order to reduce corrosion after a misinterpretation of federal regulations.

Gov Rick Snyder noted that there has been a “remarkable improvement” in the water quality in the past year.

“This is not the end of our work in Flint,” he added, “but it is one more step along the path toward Flint’s future.”

The Republican governor has been sharply criticised by Flint residents for his handling of the water crisis.

In 2014, a state-appointed emergency manager made the decision to switch its water supply from Detroit’s water system to the untreated Flint river in an effort to save the city money. The water, in turn, leached lead from old pipes, carrying it into the homes of the 100,000 Flint residents.