Every glass of tap water and every gallon that leaves a Colorado home through the drain passes through the hands of a certified operator — and the rulebook that makes that certification mandatory, defines what it means, and decides who is qualified to hold it is Colorado Regulation 100. If you are studying for your Class D water treatment or Class 1 distribution certificate, this regulation is not background reading — it is the legal foundation of the license you are about to earn, and portions of it are directly tested on your exam.
What Regulation 100 Actually Is
Colorado's operator certification rule is formally 5 CCR 1003-2, Regulation No. 100 — Water and Wastewater Facility Operators Certification Requirements. You may sometimes see it referenced informally simply as "Regulation 100." The Colorado Secretary of State's official Code of Colorado Regulations (CCR) database is