How to Get Your Tanker Endorsement (CDL N Endorsement)
The tanker endorsement (N endorsement) is required on your CDL to drive any tanker trailer carrying liquid or gas in bulk tanks of 1,000 gallons or more. Getting it requires a written knowledge test at your state DMV — no separate driving test. Most drivers pass on the first attempt with a few hours of study. Here is the complete step-by-step process.
$10-$50
State Test Fee
20-30
Test Questions
80%
Passing Score
Same Day
Added to CDL
Key Takeaways
- The tanker (N) endorsement is added to an existing CDL — there is no separate driving test, only a written knowledge test from Section 9 of the CDL manual.
- The N endorsement is required for tank vehicles with a rated capacity of 1,000 gallons or more, and applies to any CDL class.
- The test has 20-30 multiple-choice questions and requires an 80% passing score; most drivers pass after a few hours of study.
- State test fees typically run about $10-$50, and the endorsement is usually added to your CDL the same day you pass.
- To haul hazardous liquids you need the X endorsement (N + hazmat H combined), which adds a written hazmat test, a TSA background check, and 2-4 weeks of processing.
Ahmad Qazi
Founder & CEO, O Trucking LLC
Fact-Checked by O Trucking Dispatch Team
5+ years verifying CDL endorsements for tanker, hazmat, and combination loads
Written by Ahmad Qazi, founder of O Trucking LLC, drawing on 9+ years dispatching for owner-operators. Learn more about us.
O TruckingHow to Get Your Tanker Endorsement (CDL N Endorsement) Step-by-Step (2026)
When the Tanker Endorsement Is Required
The tanker endorsement is required any time you drive a commercial motor vehicle that transports a liquid or gaseous material in a permanently or temporarily attached tank with a rated capacity of 1,000 gallons or more. This includes:
- All tanker trailer types — chemical, food-grade, petroleum, pneumatic, and cryogenic
- Straight trucks with permanently mounted tanks (fuel delivery trucks, water trucks)
- Portable tanks mounted on flatbeds when the tank capacity is 1,000+ gallons
- Vacuum trucks used for liquid waste removal
Dry Bulk (Pneumatic) Tankers Also Require the N Endorsement
Step-by-Step: How to Get Your Tanker Endorsement
Confirm you have a valid CDL
The tanker endorsement is added to an existing CDL — you cannot get it as a standalone license. If you do not yet have a CDL, you must obtain your Class A or Class B CDL first. The endorsement applies to any CDL class.
Study the CDL Manual — Section 9 (Tank Vehicles)
Download your state's CDL manual from your DMV website. Section 9 covers tank vehicles and is the source material for the test. Focus on liquid surge, stopping distance, inspection procedures, and emergency procedures. Most states use the FMCSA standard manual with minor state-specific additions.
Take practice tests online
Several free websites offer tanker endorsement practice tests with questions similar to the actual exam. Take 3-5 practice tests until you are consistently scoring 90%+ before going to the DMV. Free practice tests are available at CDL Practice Test, Cristcdl, and most state DMV websites.
Visit your state DMV and take the written test
Bring your current CDL, proof of identity, and the endorsement fee ($10-$50 depending on state). The test is taken on a computer at the DMV. You will receive your results immediately. If you pass, the N endorsement is added to your CDL the same day — some states print a new card, others issue a temporary document while the new card is mailed.
If you fail, you can retake the test
Most states allow you to retake the tanker endorsement test after a waiting period (typically 1-7 days, varies by state). You may need to pay the testing fee again. There is no limit on retakes in most states. Study the specific questions you missed and take more practice tests before your next attempt.
Test Format & What to Expect
The tanker endorsement test is a written (computerized) knowledge test. Here is what to expect:
Number of questions
20-30 multiple-choice questions (varies by state)
Passing score
80% (typically 16 out of 20 or 24 out of 30)
Time limit
No time limit in most states (typically 20-30 minutes)
Driving test required?
No — written test only for the N endorsement
Key Study Topics for the Tanker Test
The test draws from CDL Manual Section 9. Here are the most frequently tested topics:
Liquid surge and its effects — What causes surge, how it affects braking and turning, why partially loaded tanks are most dangerous, how baffles reduce surge. This is the most heavily tested topic.
Baffled vs unbaffled (smoothbore) tanks — What baffles do, why food-grade tankers are unbaffled, how bulkheads differ from baffles, stopping distance differences between baffled and smoothbore.
Tank vehicle inspection procedures — What to check on pre-trip (valves, seals, manhole covers, emergency vents, leak detection), how inspection differs from a standard pre-trip, items specific to tanker safety.
Emergency procedures — What to do if a tank leaks or a valve fails, safe stopping procedures, when to use emergency vents, who to contact, and how to secure the scene.
High center of gravity and rollovers — Why tankers are prone to rollover, how speed on curves causes rollovers, the relationship between load height and stability, and safe speeds for curves and exit ramps.
Outage (ullage) and why tankers are not filled to 100% — Thermal expansion of liquids, the purpose of leaving empty space, what happens if a tank is overfilled, and how outage affects surge.
Study the 'Why,' Not Just the 'What'
Getting the X Endorsement (Tanker + Hazmat Combined)
If you want to haul petroleum, chemicals, or cryogenic gases, you need both the tanker (N) and hazmat (H) endorsements. Together, these become the X endorsement on your CDL. Here is what the hazmat endorsement adds:
- Additional written test — 30 questions on hazardous materials classification, placarding, shipping papers, and emergency response
- TSA background check — Fingerprinting and a federal security threat assessment (takes 2-4 weeks)
- Additional fee — Approximately $86.50 for the TSA background check plus the state test fee
- Renewal required every 5 years — The hazmat endorsement expires with your CDL and requires a new background check at renewal
The X Endorsement Pays for Itself Quickly
Tanker Endorsement Fees by State
Endorsement test fees vary by state. Here are representative costs (always verify with your state DMV as fees change periodically):
| State | N Endorsement Fee | H Endorsement Fee | TSA Background |
|---|---|---|---|
| Texas | $11 | $11 | $86.50 |
| California | $36 | $36 | $86.50 |
| Illinois | $20 | $20 | $86.50 |
| Florida | $10 | $10 | $86.50 |
| Ohio | $23.50 | $23.50 | $86.50 |
Test Day Tips
Bring the right documents — Current CDL, proof of identity (varies by state), and payment for the test fee. Check your state DMV website for specific document requirements before going.
Schedule an appointment — Many DMVs require appointments for CDL endorsement tests. Walk-ins may face long waits or be turned away. Schedule online or by phone to guarantee your spot.
Read each question carefully — Test questions often include words like “most,” “least,” “always,” and “never” that change the correct answer. Do not rush — there is no time limit.
Take both tests on the same day — If you are getting the X endorsement, schedule both the tanker (N) and hazmat (H) tests for the same DMV visit. This saves a trip and gets both endorsements processed together.
Common Mistakes That Cost Drivers Time and Money
- Assuming the 1,000-gallon rule is per individual tank. Multiple smaller tanks that total 1,000+ gallons can still require the N endorsement — verify the aggregate rule with your state DMV.
- Memorizing answers instead of understanding surge. The test rewords questions, so rote answers fail; learn why surge, outage, and high center of gravity matter.
- Forgetting the X needs a TSA background check. The hazmat portion takes 2-4 weeks, so do not accept hazmat tanker loads assuming you can get the X in a single day.
- Showing up without an appointment or the right documents. Many DMVs turn away walk-ins; bring your current CDL, accepted ID, and the test fee.
- Letting the hazmat endorsement lapse. It renews with your CDL and requires a fresh background check — a gap means you cannot legally haul hazmat tanker loads.
Frequently Asked Questions
How many questions are on the tanker endorsement test?
The tanker (N) endorsement test has 20-30 multiple-choice questions depending on your state, drawn from Section 9 (Tank Vehicles) of the CDL manual. You need 80% to pass — typically 16 of 20 or 24 of 30 correct. There is no driving test for the N endorsement.
Do you need a tanker endorsement for under 1,000 gallons?
The N endorsement is required when a tank has a rated capacity of 1,000 gallons or more. Smaller individual tanks can still trigger it: if a vehicle carries multiple tanks that total 1,000+ gallons, or an individual tank rated over 119 gallons within that aggregate, the tanker endorsement applies. Verify the exact rule with your state DMV.
What is the difference between the N and X endorsements?
The N endorsement lets you drive tank vehicles carrying non-hazardous liquids or gases. The X endorsement is the tanker (N) and hazmat (H) endorsements combined, which you need to haul hazardous liquids like petroleum or chemicals in a tank. The X requires the extra hazmat test and a TSA background check.
How long does it take to get a tanker endorsement?
If you already hold a CDL, the N endorsement can be done in a single day — study a few hours, pass the written test, and most states add it to your CDL the same day. The X endorsement takes 2-4 weeks longer because the hazmat portion requires a TSA background check.
Deciding between endorsements? Compare the requirements and pay in our hazmat vs. tanker endorsement guide, or follow the full process in our how to get a hazmat endorsement guide.
How Our Team Verifies Tanker Endorsements
At O Trucking LLC, we verify every carrier's CDL endorsements before booking tanker loads:
Endorsement verification on every tanker load
Before booking any tanker load, we verify that your CDL has the correct endorsements — N for non-hazmat tanker loads, X for hazmat tanker loads. We also verify that your hazmat endorsement has not expired and that your TSA background check is current. This prevents compliance violations and roadside inspection failures.
Endorsement renewal reminders
We track endorsement expiration dates for our carriers and send reminders when renewals are approaching — especially the hazmat endorsement, which requires a new TSA background check that takes 2-4 weeks to process. Proactive renewal means no gaps in your ability to haul hazmat tanker loads.
Got Your Tanker Endorsement? Let Us Find You Loads
Our dispatchers specialize in matching tanker-endorsed drivers with premium loads. Whether you have the N or X endorsement, we find loads that match your qualifications and maximize your earnings.