On April 25, 2014, a group of smiling officials in Flint, Mich., stood in front of television cameras, held their glasses aloft and toasted the switch to the city’s new water source, the Flint River.

“Here’s to Flint!” Dayne Walling, the mayor, said, taking a gulp of river water.

The Flint water crisis was born that day. Almost immediately, Flint residents began telling their elected officials that there was something wrong with the water, which smelled terrible, tasted like metal and seemed to give them skin rashes. They confronted elected officials outside City Hall, hoisting bottles full of rust-colored water from their taps, only to be told, again and again, that the water was fine.

The water was not fine. Flint officials had failed to add needed corrosion controls to the river water. Lead from the city’s old pipes leached into the water, causing alarmingly high lead levels in the blood of many residents. The outcry that followed forced a change in the city’s leadership, criminal charges against state and local officials and a yearslong effort to replace Flint’s dangerous lead pipes.

But in Flint, the water crisis is by no means in the past.

“It’s a community that’s still dealing with the trauma and the aftermath of having been poisoned at the hands of the government,” Karen Weaver, who replaced Mr. Walling as mayor largely because of anger over the water crisis, said in an interview this week. Ms. Weaver continues to tell residents to drink only bottled or filtered water.