All wastewater will contain fecal coliforms. These bacteria are present in the intestines of all warm-blooded animals, including humans. Although they are important in digestion, they are indicators that pathogens may be present. Pathogens like Giardia, Cryptosporidia, Salmonella, Shigella, Vibrio cholerae, etc., will be present only if those using the wastewater treatment system are infected.
However, since it is unlikely you will ever know the health conditions of those using a particular system, always assume that health risks exist. Pathogens are present in wastewater and can be found anywhere and on anything that is in contact with wastewater. This means they will be found
