Key takeaways
Key facts
| Fact | Detail | Source |
|---|---|---|
| Passing score | You need a score of at least 70% to pass a TCEQ licensing exam. | 30 TAC §30.20(b), Examinations; also TCEQ Water System Operators page [2] |
| Exam time | The Class D water exam has a 3-hour time limit. | TCEQ, Computer-Based Testing for Occupational Licenses [3] |
| Number of questions | TCEQ does not publish how many questions the Class D water exam has, or how much each subject counts. It publishes only the list of subjects. | TCEQ, Public Water System Operators: What Applicants for Licensing Need to Know [4] |
| Testing center fee, each attempt | Each testing center charges its own fee for every attempt. Sam Houston State University charges $53.50, not refundable. | Sam Houston State University Testing Center, TCEQ [5] |
Water exam pass rates in 2024
From January 1, 2024 to January 1, 2025[1], from a 2025 TCEQ presentation.
| Exam | Sittings | Passed | Pass rate |
|---|---|---|---|
| Water Class D | 3,968 | 1,502 | 38% |
| Groundwater Class C | 750 | 309 | 41% |
| Surface Water Class C | 424 | 231 | 55% |
| Distribution Class C | 968 | 447 | 46% |
| Groundwater Class B | 232 | 92 | 40% |
| Surface Water Class B | 325 | 105 | 32% |
| Distribution Class B | 415 | 109 | 26% |
| Water Class A | 578 | 147 | 25% |
Source: TCEQ Training Provider Updates 2025 (slides), Exam Analysis [1]
How many water exams are taken each year
In 2024 TCEQ gave 7,660 water operator exams, and 2,942 passed[1]. Class D was more than half of them: 3,968[1].
Wastewater pass rates in fiscal year 2024
TCEQ’s fiscal year 2024 runs from September 2023 to August 2024[6]. TCEQ gives the percent only.
| Exam | Pass rate |
|---|---|
| Treatment Class D | 53% |
| Provisional Treatment Class D | 20% |
| Treatment Class C | 36% |
| Treatment Class B | 44% |
| Treatment Class A | 18% |
| Collection Class I | 61% |
| Collection Class II | 38% |
| Collection Class III | 28% |
Source: TCEQ Environmental Trade Fair, June 3 2025: Occupational Licensing Updates (slides) [6]
What these figures don’t say
- They count exam sittings, not people.
- They don’t split first attempts from later ones.
- They don’t split exams taken in Spanish from exams taken in English.
What makes the Class D water exam hard
What happens if you don’t pass the exam
You may sit again once you have your result, as long as your application is approved. The application expires after 365 days or after four failed attempts at the same exam[2]. Each attempt pays the testing center’s fee[5].
How to practice for the Class D exam
OperadorListo is independent practice software for the TCEQ Class D water exam, in English and Spanish, with every math problem worked step by step. Start with the free check.
Frequently asked questions
What share pass the Class D water exam?
In 2024, 38% of Class D water exam sittings passed: 1,502 of 3,968[1].
What score passes a TCEQ exam?
You need a score of at least 70% to pass a TCEQ licensing exam.[2]
Is the Class D wastewater exam easier?
More pass: in fiscal year 2024, 53% passed wastewater treatment Class D[6], against 38% for water Class D[6]. They are different exams, with different subjects.
How many questions are on the Class D water exam?
TCEQ does not publish how many questions the Class D water exam has or how much each subject counts. Our practice exam has 50 questions, spread across the 8 published subjects with our own weights.
Sources
- TCEQ Training Provider Updates 2025 (slides), Exam Analysis, slide 12, Water Occupational Licenses, Date Range 1/1/2024 - 1/1/2025; slide 12; slide 12, totals row (read November 13, 2026)
- 30 TAC §30.20(b), Examinations; also TCEQ Water System Operators page, (b) "The minimum passing score for an examination is 70%."; (c) no repeat until notified of results; (d) 365 days or four failures (read November 13, 2026)
- TCEQ, Computer-Based Testing for Occupational Licenses, NOTE: All exams have a 3 hour time limit unless otherwise noted; Authorized Aids During Licensing Exams (read November 13, 2026)
- TCEQ, Public Water System Operators: What Applicants for Licensing Need to Know, Need-to-Know Criteria for Class D Water Operators (subjects, no counts or weights); Class D, Math (read November 13, 2026)
- Sam Houston State University Testing Center, TCEQ, Registration/Administration/Test fee $53.50; all fees non-refundable, non-transferable (read November 13, 2026)
- TCEQ Environmental Trade Fair, June 3 2025: Occupational Licensing Updates (slides), Water Exam Pass Rates - Fiscal Year 2024; Wastewater Exam Pass Rates - Fiscal Year 2024 (read November 13, 2026)
Reviewed November 13, 2026. Published by OperadorListo. The sources above are the authority. This is a summary in our own words: check the source before you act on it.