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 Water Treatment and Distribution System January 13, 2017 Water Treatment | Well Construction April 17, 2018 State Certification Information | California Wastewater Operator Certification Program July 13, 2018 Post author: Post published:January 28, 2017 Post category:Certification Exams / Distribution / Wastewater Treatment