Almost a third of U.S. adults aren’t drinking enough water. A new study from Harvard T.H. Chan School of Public Health shows that poorer adults, Black adults, and Hispanic adults are more likely to be dehydrated than wealthier and white adults.

The study authors believe a big reason for these differences is that many people just don’t have access to clean, safe drinking water. Think about the water problems in places like Flint, Michigan- that’s a perfect example.

This study came out online on July 20, 2017, in the American Journal of Public Health.

Why Clean Water Access Makes a Difference in How We Hydrate

It’s pretty clear: if your water isn’t good, you won’t drink it. Public health experts have written a lot about this connection. When people think their tap water is unsafe- or when tests show it’s got lead, nitrates, or germs- they naturally drink less of it. The problem is, bottled water isn’t an easy fix for everyone. Low-income families spend a much bigger chunk of their money on bottled water compared to wealthier households, who might just install a filter at home.

That’s where point-of-use water treatment comes in. These systems offer a real way to close this gap. Reverse osmosis (RO) systems, for instance, remove over 95% of bad stuff like lead, arsenic, fluoride, nitrates, and many other chemicals. Whole-house carbon filters make water taste better and get rid of chlorine byproducts, which encourages people to drink more tap water instead of sugary drinks.

More and more, city water utilities in underserved areas are using advanced membrane filters and UV disinfection to clean water right at the source. For homes, small under-sink RO systems now cost as little as $200-$400 installed. This makes high-quality filtered water available to a lot more people. Also, community water kiosks- basically purified water vending machines in areas that lack healthy food options and in low-income neighborhoods- are working well in California, Texas, and Florida. They’re helping more people get safe drinking water.

To fix hydration inequality, we need two things: cities need to invest in their water systems, and homes need easy access to water treatment. Water treatment companies that work in underserved communities play a direct role in closing the hydration gap the Harvard researchers pointed out.