India, Oct. 15 -- Most of us probably don't even think twice about filling up a water bottle at school. You turn on the tap, take a sip, move on. For kids in Flint, Michigan, that small habit stopped feeling safe. A 2016 paper in the American Journal of Public Health found that more young children in Flint had high blood lead levels after the city switched its water source. In 2018, Elon Musk came to the rescue with a donation of $480,350 for school water filters, though it would be years before students could safely use them, according to a Fortune report on the donation.

The city of Flint switched its source of drinking water to the Flint River in April 2014. It switched back to the Detroit water system in October 2015. The study sugge...