Missouri Water Treatment Operator Certification
Regulatory Authority
Drinking water treatment operators in Missouri are certified by the Missouri Department of Natural Resources (DNR). Certification spans four classes — Class D through Class A — corresponding to increasingly complex facility classifications, with Class D the entry-level credential and Class A covering the largest, most complex treatment plants.
Renewal
Certificates are valid for 3 years, requiring a 60-hour (or department-specified) renewal training requirement and a renewal fee (approximately $60). Exams require a 70% passing score.
Source Water Diversity
Missouri's drinking water sources vary significantly by region:
- Ozark Plateau (southern Missouri): karst geology with springs and cave systems feeding groundwater supplies. Karst aquifers are especially vulnerable to rapi