Answered
What is on the Texas Class D wastewater exam?
The Texas Class D wastewater exam covers the whole plant: rules and permits, safety and the lab, collection and pumping, preliminary and primary treatment, biological treatment, disinfection and effluent, solids and biosolids, and basic operator math. It is closed-book, and you need 70 percent to pass.
Last reviewed 2026-08-03
The areas
Most of the exam is operational knowledge: how wastewater is collected, treated through its stages, disinfected, and discharged under the plant's permit, plus solids handling and safety. A smaller share is operator math.
Why the scope matters
The exam draws from the published TCEQ scope for this exact license. Generic or higher-grade material adds topics you will not be tested on. Study the Class D wastewater scope, in the exam format.
Common questions
- Is it mostly math?
- No. Most questions are operational knowledge; a smaller share is basic math.
- Is it closed-book?
- Yes.
- What score passes?
- A minimum of 70 percent.