Correct.

Flint was on the Detroit water supply, and then tried to save money by switching to one that the pipes couldn't handle, which damaged the protective coating on the pipes and let lead leach into the water.
After the coating was damaged there was no real way to fix it that was better than "replace the pipes", which was on the agenda anyway.

Lead pipes are bad, but they're typically safe enough that it's not an emergency due to the coating. It's a worldwide effort to replace lead pipes with other materials that's usually happening roughly inline with the usual service replacement schedule, but some places are going faster because of public concern or just a good opportunity. (My local water supply got the budget to do it while doing a different project, so it took two or three times as long, but happened a few decades early and was much cheaper, then when Flint happened they looked great by being able to respond to questions by saying they started years ago and are almost done)