This is when the poisoning started:

April 24, 2014
By Dominic Adams

FLINT, MI – It will take two days (click here) before Flint residents can taste history.

On Friday, April 25, Mayor Dayne Walling turned off the flow of water from Detroit and officially ended Flint’s nearly 50-year dependence on its neighbor to the south.

Officials said it will take about two days before the Flint River water will completely work its way through the treatment plant and flow from resident’s faucets.

The city plans to use the Flint River until the Karegnondi Water Authority pipeline is built, which will bring untreated Lake Huron water to Genesee County....