Why did the flint water crisis occur?

Michigan changed their water sources to Flint River, and their water treatment leaked lead water from a pipes into the drinking water

Explanation:

The water crisis in Flint, Michigan began when the city’s drinking water became contaminated with lead, bacteria and other pollutants started in 2014. It started when Michigan changed water sources from Lake Huron and the Detroit River to the cheaper Flint River as its water source.The  residents complained immediately about discolored, tainted water. This happened because of insufficient water treatment, lead leaked from the lead water pipes into the drinking water, and exposing over 100,000 residents

um is there supposed to be choices?

the answer i chose to believe is 'harmony'