Can arsenic exposure from drinking water cause lasting changes to your DNA?

What's actually in it

Arsenic gets into drinking water from naturally occurring minerals in rock, especially in the western US, New England, and many other regions worldwide. Even at levels below the EPA limit of 10 ppb, long-term exposure has health consequences.

Beyond the direct DNA damage arsenic is known to cause, newer research shows arsenic also disrupts epigenetics, the system of chemical tags on DNA that control which genes are active. These changes don't mutate the gene sequence, but they change how the gene functions.

What the research says

A 2026 study building an epigenetic map of arsenic exposure in humans identified specific patterns of DNA methylation changes associated with arsenic exposure. These changes affected genes involved in cancer pathways, metabolism, and immune function. Some changes persisted in people who had reduced their arsenic exposure, suggesting they're not easily reversed.

This is significant because epigenetic changes can sometimes be passed to children. The concern isn't just what arsenic does to you, it's what it does to the gene regulation systems you pass on.

Check your local water quality report. If your tap water is above 5 ppb arsenic, a reverse osmosis filter is the most effective removal method. Standard carbon filters do not remove arsenic.