Maryland Wastewater Class 5A Practice Test
Built to the Maryland Board's published Wastewater 5A exam study guide, the only content outline MDE publishes. The real exam is 125 questions; this bank mirrors its weighting: secondary treatment is the largest block, tertiary treatment next (nitrification, denitrification, phosphorus removal, filtration), then solids handling, maintenance, secondary-treatment math, disinfection, safety, and lab interpretation. Maryland exams are written to the Board's own need-to-know criteria and delivered through PSI at 69.5 percent to pass.
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Maryland Wastewater Class 5A Practice Test
About this practice test
This Maryland Wastewater Class 5A Practice Test practice test is a free study tool for water operators preparing for state and national certification exams. The 100 questions on this exam cover the most common topics tested at this level, and every question comes with a plain-English explanation so you can actually learn the material.
You’ll also see this searched as a “free ABC wastewater practice exam,” a “wastewater 1 practice test,” a “wastewater grade 1, 2, 3, or 4 practice test,” or “wastewater operator exam questions and answers (PDF).” Class 1 is the same as Grade 1 in states that number them that way. It’s the same ABC-aligned material either way, free and online with a plain-English explanation on every answer. All four classes live on the wastewater treatment test hub.
If you're studying for the certification exam, we recommend taking this test once, reviewing the explanations for any questions you missed, and then taking it again later. You can also explore the other practice tests covering specific topics like disinfection, filtration, and operator math. If you want a structured walk-through of what to study and in what order, see our 30-day study plan.
What this test covers
Here's what the 100 questions cover, and how many of each you'll see:
- Equipment & maintenance (9 questions)
- Operator safety (7 questions)
- Activated sludge & process control (6 questions)
- Anaerobic (6 questions)
- Nitrification (6 questions)
- Basics (5 questions)
- Troubleshooting (5 questions)
- Biop (4 questions)
- Denitrification (4 questions)
- Preliminary & primary treatment (3 questions)
- Pumps & motors (3 questions)
- Ras (3 questions)
How to study with it
Take the whole test, then go back through the ones you missed and read why the right answer is right. Spend a little time on those topics, wait a few days, and take it again. Make a free account if you want the site to keep your scores.
Common questions
How many questions is it?
100. You can do a short set or all 100. Every question shows the right answer and a quick reason why.
Is it free?
Yes. Every test here is free, and you don't need to sign up to start.
Are these the real exam questions?
No. They're practice questions built to match the topics and difficulty of the real test. The actual exam questions aren't public.