Water Treatment ProcessesIntermediate 14 min read

Illinois Water Treatment Operator Certification: Structure, Sources & Regulatory Landscape

How Illinois structures its Class D-A drinking water operator certification, the state's split between Lake Michigan surface water and deep aquifer groundwater sources, and the regulatory pressures reshaping both.

Illinois Water Treatment Operator Certification

Certification Structure

Illinois EPA certifies drinking water operators under 35 Ill. Adm. Code into four classes based on facility complexity and required experience:

Class D — limited to pumpage, storage, or distribution-only water supply operations (no treatment processes). Requires 890 hours of qualifying experience.
Class C — adds basic treatment processes. Requires 1,780 hours.
Class B — adds more complex treatment (chemical feed, aeration & filtration, coagulation/sedimentation, membrane filtration). Requires 5,340 hours.
Class A — the highest classification, covering the most complex facilities. Also requires 5,340 hours at the Class A level.

Certificates are typically renewed on a recurring cycle with continuing education requirements set by Illinois EPA's Operator Certification program.

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