Flint isn't alone when it comes to problems with lead-contaminated tap water.
A new report from the Natural Resources Defense Council says more than 5,000 water systems around the country had lead violations in 2015.
That comes out to more than 18 million Americans who were served by lead-contaminated water systems last year.
The report, which analyzed data from the Environmental Protection Agency, may not even show how big the problem really is, according to Erik Olson with the NRDC.
Olson says many water systems with known or suspected water violations don't even show up with lead violations in the federal government's database.
That includes Flint. While the city is considered an extreme example, Olson says Flint "highlights a much broader problem with environmental injustice in America."
"The glaring omission that Flint doesn't show up highlights what we're very concerned about, which is severe under-reporting and gaming of the system to avoid finding lead problems," Olson said. "In other words, a water system can avoid detecting lead in their water if they're savvy and understand how the rules work."
According to the report, nearly 90 percent of violations that were documented did not result in formal enforcement actions from states or the EPA, while three percent resulted in penalties.
The NRDC is calling for an immediate and swift fix for the Flint water crisis, greater investment in the nation's water infrastructure and a stronger federal Lead and Cooper rule.