Water Quality A bacterium, virus, or other microorganism that can cause disease. Tags: Certification Exam Prep, Distribution System, Pathogen, Water Quality, Water Treatment Read more articles Previous PostLime SofteningNext PostWater Main Installation You Might Also Like Public Water Systems January 16, 2017 Source Water January 30, 2017 Problem Solved: Chlorine Pounds Per Day – Distribution Math June 30, 2016 Post author:jay@americanwatercollege.org Post published:January 28, 2017 Post category:Certification Exams / Distribution / Wastewater Treatment