Microbial
Total Coliform in U.S. tap water
605 public water systems across 35 U.S. states report Total Coliform in their annual Consumer Confidence Report. None currently sit at or above the federal limit.
What it is
A group of bacteria used as an indicator of overall water-system sanitation.
Why it's regulated
Coliforms themselves are usually harmless, but their presence signals that disease-causing organisms could enter the system.
Within the federal limit (302)
Showing 50 of 302. The full list is in the JSON API.
Total Coliform by state
Every state where a public water system reports Total Coliform in its annual report, ranked by systems at or above the federal limit.
Frequently asked
+What is Total Coliform?
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.
+What is the federal limit for Total Coliform in drinking water?
The federal MCLG 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.
+How many U.S. water systems have Total Coliform over the federal limit?
Zero of the 605 public water systems in The Water Map dataset currently report Total Coliform at or above its federal limit.
+Which states report the most Total Coliform in their drinking water?
No state currently has a system reporting Total Coliform at or above its federal limit in The Water Map dataset. California, Texas, Maryland have the most systems measuring it.
+How can I check if Total Coliform is in my city's tap water?
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.