The tanker endorsement test has 20 questions, and you need to answer at least 16 correctly to pass
The tanker endorsement (HE) test is a written exam administered by your state's Department of Motor Vehicles or equivalent licensing authority. It covers the rules and safety procedures for transporting liquids and gases in tank vehicles. You will see 20 multiple-choice questions on the actual test, and the passing score is 80 percent — meaning you must get 16 or more answers right.
This is a shorter test than the general CDL knowledge test (which has 50 questions), but it is focused and specific. The questions come from the tanker section of your state's CDL manual, and they test whether you understand how liquid cargo behaves, how to load and unload safely, and what to do if something goes wrong.
Key Takeaways
- The tanker endorsement test contains exactly 20 multiple-choice questions, and you must answer at least 16 correctly to pass.
- You take the tanker test at your state's DMV or licensing office after you have already passed your general CDL written test.
- The test covers tank vehicle operation, cargo handling, safety procedures, and emergency response specific to liquid and gas transport.
- You can study using your state's official CDL manual, which includes a tanker section with sample questions and explanations.
- Most states allow you to retake the test the same day or within a few days if you do not pass on your first attempt.
What the tanker test covers
The 20 questions on the tanker endorsement test focus on practical knowledge you need to operate a tank vehicle safely. Topics include how liquid cargo shifts during acceleration and braking, how to inspect a tank vehicle before driving, proper loading and unloading procedures, and how to handle emergencies like spills or rollovers.
You will also see questions about placarding (the warning labels on tank vehicles), weight distribution, and how different types of cargo — food-grade liquids, hazardous materials, gases under pressure — require different handling. The test assumes you already know the basics of CDL operation; it adds the layer of knowledge specific to tanks.
How to prepare for the 20 questions
Your state's CDL manual contains a dedicated tanker section with the same types of questions you will see on test day. Read through this section carefully, paying attention to the explanations for each answer, not just the correct choice itself. Understanding why an answer is right helps you answer similar questions you may not have seen before.
Many states also publish sample tests or practice questions online through their DMV website. Taking these practice tests under timed conditions — giving yourself the same time limit as the real test — helps you build speed and confidence. If your state does not offer free practice tests, commercial CDL study sites often include tanker practice questions as well.
Study in short sessions over several days rather than cramming the night before. The tanker test is not long, but the concepts are specific, and spacing out your study helps the information stick.
When you take the tanker test
You take the tanker endorsement test after you have already passed your general CDL written test and any other endorsement tests you need. You cannot take the tanker test first; it is an add-on to your CDL, not a standalone license.
At your DMV appointment, you will sit at a computer or receive a paper test, answer the 20 questions, and receive your score when ready or within a few minutes. If you pass, the tanker endorsement is added to your CDL. If you do not pass, most states let you retake it the same day or schedule another appointment within a few days.
Retaking the test if you do not pass
A score of 15 or lower means you did not pass. You will need to study the material you missed and try again. Some states charge a small fee for each test attempt; others do not. Check with your local DMV about their retake policy and any associated costs.
When you retake the test, you will see 20 new questions (not the same ones), so studying the same practice materials again is still useful. Focus on the areas where you struggled the first time — if you missed questions about cargo shift, for example, spend extra time on that section of the manual.
Tanker endorsement test compared to other CDL tests
| Test | Number of Questions | Passing Score | When You Take It |
|---|---|---|---|
| General CDL Knowledge | 50 | 40 correct (80%) | First, before any endorsements |
| Tanker Endorsement | 20 | 16 correct (80%) | After passing general test |
| Hazmat Endorsement | 30 | 24 correct (80%) | After passing general test |
| Passenger Endorsement | 20 | 16 correct (80%) | After passing general test |
The tanker test is one of the shorter written tests in the CDL system, but it is not easier — it is just more focused. You will not see questions about passenger safety or hazmat regulations on the tanker test; you will only see questions about tank vehicles.
What happens after you pass
Once you pass the tanker endorsement test, your CDL will be updated to show the HE endorsement. You can then legally operate tank vehicles in your state. If you are taking the road test (the driving portion of your CDL), you may be required to demonstrate tank vehicle operation during that test as well, depending on your state's rules.
The tanker endorsement does not expire on its own; it stays on your CDL as long as your CDL is valid. When you renew your CDL, you do not have to retake the tanker test unless your state specifically requires it or you let your CDL expire.
Frequently Asked Questions
Can I take the tanker test on the same day as my general CDL test?
Most states allow you to take multiple tests on the same day, but you must pass the general CDL test first. Some DMV offices schedule all your tests back-to-back; others may ask you to schedule them separately. Call your local DMV to find out their process.
What if I fail the tanker test twice?
There is no limit to how many times you can retake the test. You study, retake it, and keep trying until you pass. Some states may require you to wait a certain number of days between attempts, so check your state's policy.
Do I need the tanker endorsement if I only haul dry goods?
No. The tanker endorsement is only required if you operate a tank vehicle — a truck designed to carry liquids or gases. If your cargo is in boxes, bags, or pallets, you do not need it. Your employer will tell you which endorsements your job requires.
Is the tanker test harder than the general CDL test?
Not necessarily harder, just different. The general test covers a wider range of topics, while the tanker test goes deeper into one specific area. If you understand tank vehicle physics and safety, the tanker test may feel easier. If that is not your strength, it may feel harder.
Can I study for the tanker test using online resources instead of the manual?
Yes. Your state's official CDL manual is the primary source, but many third-party CDL study sites include tanker practice questions and explanations. Make sure any resource you use covers your specific state's rules, since some details vary by state.