Total coliform

What is it? Coliforms are a group of bacteria. Some live in soil, plants, and rivers. Others come from the poop of animals and people. E. coli is the most well-known one that comes from poop.

Why does it matter? Most coliforms won't make you sick on their own. But if they show up in your water, it's a warning sign. Their presence can mean that poop has gotten into the water, and poop can carry germs that do make people sick.

How is it measured? You collect a water sample in a special container from the lab. They'll show you how to take the sample without getting germs from your hands or the air mixed in. The lab tests it and sends back results, usually after a day or so.

What do the results mean? For drinking water, the answer should be zero. Any coliforms at all means something needs to be looked into.

For swimming or boating, there's no rule based on total coliforms. Instead, most places test for two specific bacteria: E. coli in lakes and rivers, and a different one called Enterococci in the ocean. These are better at telling us whether the water is risky for people.