In water quality science we can count total coliform bacteria in order to determine the concentration of bacteria pre and post water treatment. We can also differentiate the types of bacteria there are. There are 2 main branches of bacteria: autotrophs & heterotrophs. Heterotrophs are bacteria like deadly E. Coli that are harmful for people if consumed.
So by differentiating type of the bacteria and the concentration of bacteria we can theorize what is causing poor water quality and what would be the best treatment to apply to the impaired source of water. These tools are important because without water that is free from bacterial contamination developers and water suppliers cannot deliver water to the public. The Total Coliform Rule is one such regulation that dictates drinking water bacterial concentration and steps to prevent bacterial outbreaks. I love when science and the regulatory world work together to protect the public the most.
Amber M. Baylor 