Texas Class D · Water and Wastewater
Pass your Texas Class D exam without wasting your time.
The Class D exam is closed-book and covers every TCEQ subject, but generic prep, random videos, and question dumps bury you in the wrong grade, the wrong state, or answers no one checked. We practice the exact TCEQ scope, every answer worked and tied to its source. First attempt or retake.
Five free problems to start. No account. Every one worked in full.
Every one original, in scope, with the full solution shown.
Scoped to your exact Class D exam. Nothing from a higher grade or another state.
Each fact ties to the TCEQ page it came from, with the date we checked it.
Do today's five and use the calculators with no account and no card.
See the depth
A real question, before you spend a dollar.
No dump, no fluff. A clean question, answers built from the mistakes operators actually make, and the full worked solution the moment you answer. Every question in the bank reads like this one.
A tank is 40 ft long, 20 ft wide, and 12 ft deep. How many gallons does it hold?
Why most people fail
The Class D exam is not hard. Studying the wrong things is.
Picture it. Your exam is three weeks out. You get home after a shift, tired, and open YouTube. Two hours later you have watched a solid video, but it was built for a Class B operator in another state, and you still cannot say what your Class D exam will actually ask.
The Class D exam is entry level, but it is broad. It touches every official TCEQ subject, and it is closed-book. People do not fail because the material is hard. They fail because they spend their limited time on the wrong material and walk in unsure what was even on it.
The fix is not more studying. It is studying the exact scope of your exam, until it is automatic.
A fair question
Why pay when YouTube and ChatGPT are free?
It is the right question to ask. Free tools are good for a lot. Here is the honest case for where they fall short, and where we do not.
Free, but built for whoever the creator had in mind, often a higher grade or another state. Watching is passive, and you cannot tell which sixty minutes match your exam.
A daily set scoped to your exact Texas Class D exam, so the time you spend after a shift is time that counts.
It answers with total confidence, and it is wrong often enough to hurt you: an invented answer key, a subtly wrong conversion, a limit it made up. It never tells you when it is guessing.
Every number is re-derived by code, and every fact ties to a real TCEQ page with the date we checked it. Nothing here is a guess.
Recalled questions break the exam agreement you sign, and the crowd-sourced answer keys are often wrong. You memorize letters that fall apart the moment the numbers change.
Original questions, written for one exact exam, that teach the method, so it holds up no matter how the question is worded.
What you get
A plan for your exact exam, not a pile of content.
See what to study next
With the full setA short diagnostic reads which subjects are solid and which need work, then points you straight at the next thing to practice.
Your limited time goes where it moves your score, not where you are already strong.
Today's 5
Free nowFive problems for your exact exam, fresh every day, that you can finish after a shift. Answers checked as you go.
A habit you can actually keep, not a list you abandon.
The full question bank
With the full setOriginal questions across every official TCEQ subject, each with the complete worked solution.
Practice the whole exam, not just the handful of topics that are easy to find online.
Every answer, worked and sourced
In everythingMath is worked one step at a time; each fact links to the TCEQ page it came from, with a review date.
You never have to wonder whether an answer is right.
Free operator calculators
Free nowTank volume, chlorine dosage, flow, and more, each worked in full with every step shown.
Real tools you can use on the job today, at no cost.
Built for after a shift
Free nowPhone-first, a few minutes at a time, and your progress saves on your device and carries into the full set.
Prep that fits a working operator's day, not a student's.
Pick your exam
Which one are you studying for?
Water and wastewater are separate licenses. Pick yours, and every question, subject, and calculation is scoped to that exact TCEQ exam, with nothing from the other track or a higher grade mixed in.
Groundwater and surface water basics, storage and distribution, disinfection, and the operator math on the Class D water exam.
Start free practiceCollection and treatment, ponds and trickling filters, disinfection, and the operator math on the Class D wastewater exam.
Start free practiceHow it works
See where you stand in a few minutes.
Find your weak spots
Start with today's five or the diagnostic. Answers are checked as you go, so you get a fast, honest read on where you stand.
Practice the right things
Work the exact TCEQ subjects and math on your Class D exam, each answer worked in full, a few minutes at a time.
Walk in ready
The questions mirror the format and scope of the real exam, so nothing on test day is a surprise.
Why you can trust it
Built to be trusted, not just to sell.
We cannot promise you a result, so we do the next best thing: we are exact about what serves and where every answer comes from.
Only what is on your exam
Scoped to the exact TCEQ Class D subjects and math. Higher-grade and out-of-state material is left out on purpose.
Every number re-derived by code
No calculation is typed by hand and hoped for. Each one is computed and checked before it serves.
Every fact tied to a source
Requirements, limits, and rules link to the exact TCEQ page, with the date we last checked them.
Original, never recalled
Every question is written from scratch for one exact exam. We never use recalled, leaked, or dumped questions.
Honest about your result
We show what to study and why. We never promise a result or claim to know your score, because no honest tool can.
Independent of the TCEQ
We are not affiliated with the TCEQ or any testing vendor. The official word always comes from the sources we link.
Simple pricing
One payment. No subscription.
Start free. When you want the full bank, it is a single one-time purchase, priced by how long you need it. Nothing auto-renews, and nothing is saved to bill you later. The exam costs $111 to sit, and a retake is that fee again plus weeks of waiting, so the full set is less than one retake.
One payment. Best if your exam is booked soon.
- The full question bank, every subject
- Today's 5 and focused practice
- Every answer worked and sourced
- Progress saved to your account
One payment, about $43 a month. Best if your exam is weeks out.
- Everything in the 30-day plan
- A real study window, at your pace
- No auto-renew, nothing to cancel
- Progress saved to your account
The full bank is opening now, and your free progress carries over. Start free today, no account or card needed.
Free study resources
Everything you need, free to start.
Worked problems, the math solved step by step, plain-language operator terms, and straight answers to the questions people actually ask. All free, all scoped to your exact Texas Class D exam.
Questions
Straight answers.
- Why pay when YouTube and ChatGPT are free?
- Free tools give you endless generic content you cannot fully trust. ChatGPT will hand you a wrong answer with no source; YouTube cannot tell you which sixty minutes match your exam. We give you the exact scope, every answer worked and sourced, and a plan for what to study next, so your limited time actually counts.
- Is this a subscription?
- No. Each plan is a single one-time purchase. Nothing renews and nothing is saved to charge you again.
- Are these real exam questions?
- No. Every question is original and written for one exact exam. We never use recalled or leaked exam questions.
- What if I do not pass?
- We never promise a result, and no honest tool can. What we do is show you exactly what to study and why, so you walk in prepared for your exact exam.
- Which exam does it cover?
- The Texas Class D water and wastewater operator exams, bound to the official TCEQ subject and math scope. Water and wastewater are separate, and we never mix them.
- Is it really free to start?
- Yes. Today's five problems and the calculators need no account and no card. The full question bank is the paid part.
Start with today's five. Free, no account.
See where you stand in a few minutes, on the exact scope of your Texas Class D exam. Build the habit now; the full bank is right there when you want it.
Do today's 5