Missouri Water & Wastewater Operator Practice Tests

Missouri's operator certification is governed by 10 CSR 60-14.010 (Classification of Public Water Systems), 10 CSR 60-14.020 (Certification of Public Water System Operators), and 10 CSR 60-14.030 (Operator Training). DNR issues two separate drinking-water certifications: Drinking Water Treatment Operator (Class A highest through Class D entry) and Drinking Water Distribution Operator (DS-III highest, DS-II, DS-I entry). Treatment experience requirements: Class A = 5½ years; Class B = 3½ years; Class C = 1½ years; Class D = 6 months (with up to 2 years/1 year equivalent allowed). Distribution experience requirements: DS-III = 3 years; DS-II = 1 year; DS-I = 6 months. All applicants must be at least 18, possess a high school diploma/GED (or department-approved training, or 6 additional months hands-on experience), and pass a multiple-choice exam at 70%. The application/exam fee is $50 (covers exam plus certificate issuance). Exam sessions are monthly in Jefferson City and quarterly at five regional locations; applications are due 30 days before the exam. If you pass the exam but lack the experience, you have 18 months to accumulate it. Failed exam = 60-day wait before retest; three failures requires a department-approved multi-day training course. Certificates are valid for 3 years and renewal requires class-specific approved training (Treatment A/B/C = 30 hours; D = 20 hours; Distribution DS-III = 30; DS-II = 20; DS-I = 10) plus a $60 renewal fee. A 60-day grace period applies after expiration with a $37.50/month late fee; failing to renew results in deactivation and the operator must retest.

No. These are independent practice tests designed to mirror the technical material and difficulty of the Missouri certification exam. The official exam is administered by Missouri DNR (Department of Natural Resources) — Division of Environmental Quality, Operator Certification Section (or its testing vendor) and the exact questions are not public.

Yes — every practice test on this site is free, with no paywall. The site is supported by affiliate partnerships with established water operator training providers (announced when ready) — but the practice tests themselves stay free.