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 Softening Next PostWater Main Installation You Might Also Like January 24, 2017 How to Study for Water Treatment License Exams – Part 9 of 10 October 29, 2018 Texas Water License Exam Prep 2 of 2 February 19, 2019 Post author: Post published:January 28, 2017 Post category:Certification Exams / Distribution / Wastewater Treatment