DENVER — Maria Cruz stays away from the tap. So does Monserrat Trejo. And then there is Lucero González — also an immigrant from Mexico — who, on a recent afternoon, shoved a shopping cart across the parking lot at Mi Pueblo Market. Inside: Nothing but water. Ninety-six bottles of it.

“I only drink from the tap when I have no money,” said Ms. González, 45, a petite nurse’s assistant, as she hefted giant pallets of plastic into her sport utility vehicle. She arrived in the United States in 1988, but said she was still unsure whether the nation’s water was healthy.

At a time when water crises in communities like Flint, Mich., and Newark, have eroded confidence in public water systems — particularly those in poor and minority communities — a health outreach initiative in Colorado is trying to dispel the notion that all tap water is harmful. The initiative, mainly aimed at Latino immigrants, delivers the message that Denver’s fluoride-enhanced water is actually healthier than bottled water, which typically lacks the ingredient that can prevent cavities, particularly in children.

The campaign, sponsored primarily by the health insurer Delta Dental of Colorado, began before the lead contamination in Flint and elsewhere spread fear across the country. But the crises have highlighted the obstacles in persuading Latino immigrants that American tap water is usually safe: Images of brown, poisoned water flash on television screens in living rooms and laundries here, reinforcing the preconceptions imported from places where bottled beverages are culturally ingrained.