Minnesota Water & Wastewater Operator Certification Guide

Decision 1

Choose the work before choosing the exam.

Drinking water

MDH administers mandatory water supply system operator certification. The official study page describes closed-book 100-question exams with a three-hour limit.

Treatment: source water, process control, filtration, disinfection, laboratory work.
Distribution: pumps, storage, pressure, mains, valves, sampling, flushing.

Study treatment · Study distribution

Wastewater

MPCA manages wastewater training, exam requirements, and certification. Experience and education requirements vary by class.

Treatment: biological and physical processes, solids, disinfection, compliance.
Collections: sewers, lift stations, force mains, I&I, cleaning, overflow response.

Study treatment · Study collections

Do not pay yet: Do not send a wastewater application to MDH or a drinking-water application to MPCA. The two agencies run separate programs.

Decision 2

Build the application record in the right order.

Credential map: Drinking-water Classes A–E and wastewater Classes A–D plus collection-system credentials

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Confirm the exact field and class. Ask the facility or job posting for the credential name—not simply “water license.”Open the current agency requirements. Compare education, approved training, experience, and any class prerequisites.Separate exam approval from certification approval. An application receipt or passing score may not be an active certificate.Gather records before applying. Save transcripts, course certificates, job descriptions, dates, hours, facility class, duties, and supervisor contacts.Use the current application and payment instructions. Do not mail an old form or rely on a cached third-party fee table.Schedule only after approval where required. Verify identification, calculator, formula sheet, appointment, and retest rules.Complete the certificate step. Choose drinking water or wastewater; use MDH or MPCA; document education and hands-on experience; submit the current exam application by deadline; pass; complete certification and renewal requirements.Record renewal and continuing-education dates. Save approved hours as you earn them.

Decision 3

Study from the state outline, then diagnose weak operator topics.

Minnesota exam note

Drinking-water applications go to MDH by the listed deadline. Wastewater exams require MPCA pre-registration and use the current MPCA forms.

Decision 4

Make the job produce qualifying experience.

Before accepting or paying for training, ask the employer or program these exact questions:

Which certificate, class, and facility classification does this role support?
Which daily duties count as operating experience—and which duties do not?
Who will supervise and sign the experience verification?
How are hours, shift assignments, process duties, and dates recorded?
Does the employer pay for approved training, exams, renewals, or higher-grade preparation?

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Primary sources

Open the agency page before submitting or paying.

Last reviewed: July 13, 2026. State pages and current forms control if this guide differs.

Minnesota water and wastewater operator certification