Total Coliform in U.S. tap water

A group of bacteria used as an indicator of overall water-system sanitation. Coliforms themselves are usually harmless, but their presence signals that disease-causing organisms could enter the system.

The federal Public health goal for Total Coliform is 0 %. The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.

1 of the 178 public water systems on The Water Map report Total Coliform at or above its federal limit, spanning 34 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 Total Coliform.