Cyanide in U.S. tap water

Cyanide is a contaminant some U.S. public water utilities measure and report in their annual Consumer Confidence Report.

The federal MCL for Cyanide is 0.2 mg/L. The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.

4 of the 76 public water systems on The Water Map report Cyanide at or above its federal limit, spanning 12 U.S. states. The full list is on this page.

Of the systems on The Water Map, Texas (4 systems at or above the limit) report the most Cyanide exceedances. The state-by-state table on this page lists every state.

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 Cyanide.