Four years ago, the Flint water crisis began when officials switched its source from Lake Huron to the Flint River. Its more corrosive water caused dangerous levels of lead from old pipes to leach into the city's drinking water, poisoning residents. Now, after fighting with officials just to get the problem recognized in 2015, many residents still don't trust the city's tap water. Into the fray steps Elon Musk, fresh off of his submarine-building exploits, responding to a tweet with this promise "Please consider this a commitment that I will fund fixing the water in any house in Flint that has water contamination above FDA levels. No kidding."