Coliform bacteria are associated with water that is unfit to drink as they come from fecal matter. Ideally, our drinking water would have no coliform bacteria in it, otherwise, water should be boiled to drink. Being able to perform your own coliform bacteria test is ideal if you are a well owner or have a water body on your property. It is fairly easy to do but does require some startup cost. There is a growing movement of DIY Biolabs that may have equipment available for use. The method that I will be outlining is the membrane filter method (EPA method 1604). In this method, water samples are filtered through a membrane that retains bacteria and then the samples are placed on growth medium and incubated. The bacteria grow dome-shaped colonies which are then counted after 24 hours. Please note that I am not an expert, and this article should not be used entirely for testing. Please read the EPA method and if you feel you don’t fully understand the method then have your drinking water tested by a lab.