Mayor's Office

Flint Increases Corrosion Control in Water


The City of Flint has begun the corrosion control process by adding phosphates to the City’s water distribution system.

The chemical additive comes at the recommendation of the Michigan Department of Environmental Quality (MDEQ).

The City of Flint, the MDEQ, and the EPA have worked together closely to determine the necessary amount of Phosphate to be added to the water. Phosphate is a type of salt containing the natural mineral phosphorus and is added to water distribution systems across the country for corrosion control. The phosphates build-up a protective layer inside pipes so that metals like lead and copper do not leach into the water. This protective layer is known as scale and collects on the sides of the pipes by sticking to the metal. According to Flint Utilities Director Michael Glasgow, 2.5 milligrams per liter is being added to the water. This is in addition to what Detroit is already adding. Flint is adding more phosphate to Detroit water to build-up and maintain scale faster.

Glasgow also states that the time it will take for scale to accumulate in Flint’s pipes will depend on the amount of water usage and the existing condition of the pipes, but that it should take between 2 and 6 months to see reductions in lead levels in Flint water.