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Texas · Wastewater Treatment · Class B

Texas Grade 3 Wastewater Treatment Operator Exam

The Texas Grade 3 wastewater treatment certification is designated Class B and issued by Texas Commission on Environmental Quality (TCEQ). Advanced certification for shift leads and operators at larger systems with complex processes.

Photo: MADe, CC BY 3.0

Applied math is a significant part of the Texas Class B exam.

Practicing calculations like dosage, detention time, and loading before test day is one of the most effective ways to prepare, alongside reviewing your state’s official exam content outline.

Exam facts

Exam facts
Grade levelClass B
Questions120
Time limit180 minutes
Passing score70%
DifficultyAdvanced
Exam administered byTCEQ (administered at approved testing centers)

Prerequisites for Class B

  • Grade 2 certification
  • 3–4 years of operating experience
  • Some post-secondary coursework (varies by state)

Confirm exact requirements with Texas Commission on Environmental Quality (TCEQ).

What's on the exam

  • Preliminary and primary treatment
  • Activated sludge process control
  • Secondary clarification
  • Nutrient removal (nitrogen, phosphorus)
  • Disinfection and dechlorination
  • Solids handling and biosolids
  • Advanced process optimization
  • Regulatory compliance strategy

The math on the Wastewater Treatment exam

These calculations are commonly included in wastewater treatment operator exam preparation and may appear on your exam depending on your certification level and state. Practicing them is one of the most effective ways to prepare.

  • Food-to-microorganism (F:M) ratio
  • Mean cell residence time (MCRT/SRT)
  • Sludge volume index (SVI)
  • Hydraulic and organic loading
  • Detention time
  • Pounds formula (lbs/day)

Free Class B practice questions

Sample questions with full explanations at this level.

Take the practice quiz →

Frequently asked questions

What is the Texas Grade 3 wastewater treatment certification called?
In Texas, the Grade 3 wastewater treatment certification is designated Class B, issued by Texas Commission on Environmental Quality (TCEQ).
How many questions are on the exam and what score do I need?
The exam has about 120 questions with a 180-minute time limit, and you need 70% to pass. It is administered by TCEQ (administered at approved testing centers).
What are the prerequisites for Class B in Texas?
Typical prerequisites: Grade 2 certification; 3–4 years of operating experience; Some post-secondary coursework (varies by state). Exact requirements are set by Texas Commission on Environmental Quality (TCEQ).