The charges stemming from the investigation will include felonies.
Schuette will make a formal announcement of the charges on Wednesday, April 20, 2016.
Among the charged are one Flint water department employee and two mid-level engineers with Michigan Department of Environmental Quality. One of them will be charged for falsifying government documents.
The source of water for Flint was changed from the Detroit River to the Michigan River, after the Detroit government cut off the city of Flint.
Flint had announced plans to build its own water pipelines, which would allow it to wean off its dependency on Detroit. Detroit retaliated against Flint by prematurely cutting off its water supply.