California water distribution practice test
Practice questions for the D1 and D2 distribution operator exams, written from the State Water Board range of knowledge and explained one by one. Train by topic, then take a timed 100 question mock exam.
- All 220 questions and answers
- Free practice test
- Money-back guarantee
Take the practice test
10 practice questions from the question catalog. How many can you get right?
How the California distribution operator exam works
Drinking water distribution operators in California need a certificate from the State Water Resources Control Board. You apply to the Board, take the exam at a Prometric test center and then apply for the certificate.
The D1 and D2 exams have 100 multiple choice questions each. About 15 of them are math problems, and an equivalents and formula sheet is provided. Topics include disinfection, hydraulics, mains and piping, equipment, water quality and regulations.
This site is an independent exam trainer. The certificate itself is issued by the State Water Board, not by us. Our questions are written from the official range of knowledge.
The topics of the test
The 220 questions in the catalog are spread across these areas. In the trainer you practice all of them until every area sticks.
- Disinfection29 questions
- Distribution System Design and Hydraulics33 questions
- Equipment Operation, Maintenance and Inspections35 questions
- Drinking Water Regulations, Management and Safety29 questions
- Water Mains and Piping35 questions
- Water Quality and Water Sources23 questions
- Distribution Math36 questions
How many questions can you get right?
10 practice questions, free and without signing up. At the end you see whether it would already be enough for the test.
How you learn with us
No rote memorizing from start to finish. The trainer remembers what you know and practices exactly the rest with you.
Take the practice test
10 practice questions, free. Afterwards you know where you stand.
All questions with solutions
The complete catalog with 220 questions, each with the correct answer.
Tests that adapt to you
Every round puts the questions together anew. Whatever you got wrong comes back until it sticks.
Pass or get your money back
If you fail despite practicing, you get your last payment back.
All questions and answers in the online trainer
Everything you need for the knowledge test in one place. No book, no class, on your phone or computer.
- 220 questionsAll with solutions
- 100 in 180 minutesLike in the real test
- 7 topic areasPractice targeted, one by one
- 100 %Money-back guarantee
The complete question catalog
All 220 questions that could come up, each with the correct answer. You learn exactly what gets asked.
For every question you see how often others get it wrong and which answer they mix it up with. That way you spot the traps.
Test simulation like the real thing
100 questions, 180 minutes, graded like the real test: at least 70 correct answers out of 100 (70 percent, our practice target).
Every round is shuffled anew. Afterwards you see right away whether you would have passed and what is still missing.
Practice that adapts to you
The trainer remembers what you already know. Wrong answers come back until they stick, and a question only counts as learned once you have answered it correctly several times with time in between.
You can also practice individual topics or just your weak spots.
Your plan until the test
Enter your test date and the trainer spreads the questions across the remaining days. That way a small round waits for you every day instead of cramming everything the last evening.
Your progress shows you at any time when you are ready for the test.
Short videos to swipe
Learn like on Instagram or TikTok: Every question comes as a short video, you tap your answer and swipe to the next one. Whatever you got wrong shows up more often.
Ideal for in between, on the train or on a break.
Pricing
Both options include all questions and answers and all trainer features. You only decide whether you pay weekly or once.
Weekly pass
$7.99per week
- All 220 questions and answers
- All trainer features
- Cancel anytime
Permanent access
$39.99one-time
- All 220 questions and answers
- All trainer features
- Pay once, no subscription
Our money-back guarantee applies to the subscription.
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guarantee
Our money-back guarantee
We are confident that you will pass with the trainer. If not, we refund the last payment of your subscription. The guarantee applies to the subscription, not to lifetime access.
It is that simple: Within 30 days after the test, send us a short email at [email protected] with proof, for example a photo of your test result. No follow-up questions, no form. The exact conditions are in the terms and conditions.
Frequently asked questions
What do I need for the D1 exam?
A high school diploma or GED, or one of the equivalents the State Water Board accepts. D2 also requires a 36 hour water supply course. Check the Board pages for the current rules and fees.
Is there math on the exam?
Yes. About 15 of the 100 questions are math problems such as volume, flow, chlorine dose and pressure. You get a calculator and the equivalents and formula sheet.
Are these the real exam questions?
No. The State Water Board does not publish its exam questions. All questions here are our own, written from the official range of knowledge.
Do I get my certificate here?
No. This site only helps you prepare. Certificates are issued by the State Water Resources Control Board after you pass the exam.