CNN  — 

Comedian Michelle Wolf made a lot of jokes at the White House Correspondent’s Dinner that offended people.

But buried in the controversy was the line that ended her routine: “Flint still doesn’t have clean water.”

Indeed, it’s been nearly four years since the Flint, Michigan, water crisis began, and although government officials claim the city’s tap water is back to safe levels, residents still do not trust that the problem has been fixed for good.

For all the debate around the appropriateness of Wolf’s barbs Saturday night, her blunt closing line underscored the seriousness of the long-running humanitarian crisis in Flint, where cost-cutting measures led to drinking water tainted by lead and other toxins.

The problem began in 2014, when the city switched its drinking water from Lake Huron to the corrosive Flint River. Residents said the water looked, smelled and tasted funny, and gave people rashes and caused other health problems.

Testing by the EPA in 2015 found dangerous levels of lead. Ever since, residents have been relying on government-funded bottled water for drinking, bathing, cooking and other everyday uses.

In early April, Michigan Gov. Rick Snyder announced the end of the free bottled water program, saying the city’s water was finally back to safe levels. But Flint’s mayor is trying to restart distribution of bottled water, saying all the city’s lead pipes have not been replaced.

And some Flint residents are still skeptical.

“I don’t trust the filter, I don’t trust the water,” Ariana Hawk told CNN affiliate WJRT. “Everything that me and my kids do from cooking to boiling their water for a bath, we’re using bottled water. I do not trust anything.”