Selenium in U.S. tap water

A trace element from natural deposits and industrial discharge. Essential in tiny amounts, but long-term exposure above the federal limit can cause hair and fingernail loss and circulatory problems.

The federal MCLG for Selenium is 50 ug/L. The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.

2 of the 100 public water systems on The Water Map report Selenium at or above its federal limit, spanning 21 U.S. states. The full list is on this page.

Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including Selenium.