Immigrants in the United States often deal with a fair amount of culture shock in their new home, but there’s one thing Latino immigrants in Denver are still getting used to: the drinking water.

According to The New York Times, Denver authorities are on a mission to convince Latino immigrants, especially from countries like Mexico, that tap water is safe and, in fact, can even be healthier to drink. Many who have grown up in countries where the water systems are poor just can’t seem to shake old habits.

“I only drink from the tap when I have no money,” said Lucero González, 45, a nurse’s assistant who has been in the U.S. since 1988. Despite being here almost 30 years, she’s still not sure whether she should trust the tap water supply or not.

For the most part, the deeply held belief by many in the Latino community stems from their roots growing up in countries with inadequate water supplies, but recent events in the U.S. haven’t helped instill much confidence. With communities like Flint, MI, battling lead contamination in the public eye, it’s hard to convince people who already hold a negative outlook on tap water that theirs is safe to drink.

In an effort to dispel these beliefs, the health insurer Delta Dental of Colorado started the tap water campaign, called “Cavities Get Around,” aimed primarily at Latino immigrants, to inform them that Denver’s fluoride-enhanced water is actually healthier than bottled water. Oftentimes bottled water lacks this cavity-fighting additive; in fact, 65% of parents using bottled water did not know what levels of fluoride it contained, according to one 2012 study in the Journal of Pediatric Dentistry.

“People don’t drink the water because they come from parts of Mexico, or other countries — say, in South America — where they don’t trust it,” Gabriela Medina, an educator for Denver community group Westwood Unidos, told The New York Times. “They think it’s the same here.”