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Tank endorsement and inspecting tank vehicles

Tank Vehicles (N)3 minManual section 8, 8.1

Liquids and gases in a tank make a truck behave differently, so the law asks for an extra test: the Tank Vehicle endorsement (letter N). This lesson explains when you need it and what you must check on a tank before you load, unload or drive.

When you need the tank endorsement

You need the Tank Vehicle (N) endorsement when you drive a vehicle that needs a Class A or Class B CDL and it carries a liquid or liquefied gas in one or more tanks, and:

  • each single tank has a rated capacity of more than 119 gallons, and
  • all the tanks together have an aggregate rated capacity of 1,000 gallons or more, and
  • the tank is attached to the vehicle or chassis permanently or temporarily.

The cargo does not have to be a hazardous material. Milk, water or cooking oil in a large tank still needs the N endorsement.

A Class C vehicle needs the tank endorsement when it carries hazardous materials in liquid or gas form in tanks of the sizes above.

If you haul hazardous materials in a tank, you need both the tank and the hazmat endorsements. Many states put these together as the X endorsement. To prepare for the tank test, also review manual Sections 2, 5, 6 and 9 (general knowledge, air brakes, combination vehicles and hazardous materials).

Inspect before every load, unload and trip

Inspect a tanker before loading, before unloading and before driving. The goal is to be sure the tank can safely hold the liquid or gas and the vehicle is safe on the road.

Tank vehicles come in many types and sizes. Read your vehicle's operator's manual so you know how to inspect your own tank, its valves and its special equipment.

Leaks: the most important check

On every tank vehicle, leaks are the number one item to look for. Look under and around the whole vehicle for drips, wet spots, stains or smells.

Hauling liquid or gas in a leaking tank is a crime. You will be cited and stopped from driving further, and you may have to pay for the clean-up of the spill.

Check these parts:

  • Tank body or shell: dents or leaks.
  • Intake, discharge and cut-off valves: no leaks, and each valve in the correct position before you load, unload or move the vehicle.
  • Pipes, connections and hoses: leaks, especially around joints.
  • Manhole covers: they must have gaskets and must close correctly.
  • Vents: keep them clear so they work. A blocked vent can let pressure build up or pull a vacuum.

Special purpose and emergency equipment

If your tank has any of this equipment, make sure it works:

  • Vapor recovery kits (catch fumes during loading).
  • Grounding and bonding cables (stop static sparks).
  • Emergency shut-off systems (stop product flow fast).
  • A built-in fire extinguisher.

Do not move a tanker on the road while any valve or manhole cover is open.

Also check the emergency equipment your vehicle is required to carry. Find out what is required, make sure it is on board, and make sure it works.

References and scope

The topic reference is listed below. Sources support verification; the lesson itself is here. The current content needs technical and language review before public launch.

Manual reference: 8, 8.1

Official CDL handbook · Utah ↗StatesOur editorial approach

Put it into practice

Educational questions with explanations. The answer review also works without the interactive quiz.

Preparing your questions…

Review questions with answers

  1. A Class A or B driver needs the tank endorsement to haul a liquid in a tank attached to the vehicle when each tank holds more than ___ gallons and the total is 1,000 gallons or more.
    1. 100
    2. 119
    3. 500
    4. 1,000
    Show answer
    119

    The rule is more than 119 gallons per tank and an aggregate of 1,000 gallons or more.

  2. What total (aggregate) rated tank capacity, together with tanks over 119 gallons each, requires the tank endorsement?
    1. 500 gallons or more
    2. 750 gallons or more
    3. 1,000 gallons or more
    4. 3,000 gallons or more
    Show answer
    1,000 gallons or more

    An aggregate rated capacity of 1,000 gallons or more triggers the endorsement.

  3. A Class B truck hauls 2,000 gallons of drinking water in a permanently mounted tank. Does the driver need a tank endorsement?
    1. No, because water is not a hazardous material
    2. Yes, the cargo does not have to be hazardous
    3. Only if the tank has baffles
    4. Only when the tank is full
    Show answer
    Yes, the cargo does not have to be hazardous

    The tank endorsement covers any liquid or liquid gas in tanks of the listed sizes, hazardous or not.

  4. When does a Class C vehicle need a tank endorsement?
    1. Whenever it carries any liquid
    2. Never; tank endorsements are only for Class A
    3. Only when it tows a trailer
    4. When it hauls hazardous materials in liquid or gas form in tanks of the regulated size
    Show answer
    When it hauls hazardous materials in liquid or gas form in tanks of the regulated size

    For Class C, the tank endorsement is needed when hazardous liquids or gases are carried in tanks of the listed capacities.

  5. The tank endorsement applies whether the tank is permanently or temporarily attached to the vehicle or chassis.
    1. True
    2. False
    Show answer
    True

    The rule covers tanks attached either permanently or temporarily.

  6. When should you inspect a tank vehicle?
    1. Only once a week
    2. Only after unloading
    3. Before loading, before unloading and before driving
    4. Only when a leak is reported
    Show answer
    Before loading, before unloading and before driving

    Inspect a tanker before loading, unloading or driving so it is safe to carry the product and safe to drive.

  7. Because tank vehicles come in many types, where should you learn how to inspect your particular tank?
    1. From another driver's truck
    2. In the vehicle's operator's manual
    3. On the placard
    4. From the bill of lading
    Show answer
    In the vehicle's operator's manual

    Check the operator's manual to know how to inspect your own tank vehicle.

  8. On all tank vehicles, what is the most important item to check?
    1. Leaks
    2. Paint condition
    3. Mud flaps
    4. Radio
    Show answer
    Leaks

    Leaks are the most important item on any tank vehicle inspection.

  9. What can happen if you carry a liquid in a leaking tank?
    1. Nothing, if the leak is small
    2. You only get a warning
    3. You must drive faster to deliver it
    4. You can be cited, stopped from driving, and made to pay for clean-up
    Show answer
    You can be cited, stopped from driving, and made to pay for clean-up

    Driving a leaking tank is a crime: you will be cited, stopped, and may be liable for clean-up.

  10. Where should you look most closely for leaks on pipes, connections and hoses?
    1. At the middle of each hose
    2. On the cab roof
    3. Around the joints
    4. Under the fuel tank cap
    Show answer
    Around the joints

    Look for leaks on pipes, hoses and fittings; joints are the most common spot.

  11. Before loading, unloading or moving a tanker, the intake, discharge and cut-off valves must be:
    1. Removed
    2. In the correct position
    3. Painted red
    4. Fully open
    Show answer
    In the correct position

    Each valve must be set the right way before you load, unload or drive.

  12. When checking manhole covers on a tank, you should make sure they:
    1. Have gaskets and close correctly
    2. Are left slightly open for air
    3. Are painted with the placard color
    4. Have no locks
    Show answer
    Have gaskets and close correctly

    Manhole covers must have gaskets and must close correctly.

  13. What should you check about the vents on a tank?
    1. That they are taped shut
    2. That they are removed for the trip
    3. That they face forward
    4. That they are clear so they work correctly
    Show answer
    That they are clear so they work correctly

    Keep vents clear so they work correctly.

  14. When inspecting the tank's body or shell, you are mainly looking for:
    1. Faded lettering
    2. Dents or leaks
    3. Extra mirrors
    4. Low tire pressure
    Show answer
    Dents or leaks

    The shell is checked for dents and leaks.

  15. Which of these is special purpose tank equipment you must check if your vehicle has it?
    1. A sleeper berth curtain
    2. A CB antenna
    3. Grounding and bonding cables
    4. Seat covers
    Show answer
    Grounding and bonding cables

    The special equipment list: vapor recovery kits, grounding/bonding cables, emergency shut-offs, built-in extinguishers.

  16. Which item is on the list of special purpose equipment to check on a tank vehicle?
    1. Emergency shut-off system
    2. Air conditioner
    3. Spare headlight bulbs
    4. Load locks
    Show answer
    Emergency shut-off system

    Emergency shut-off systems are on the special equipment list, with vapor recovery kits, grounding/bonding cables and built-in extinguishers.

  17. It is acceptable to drive a tank vehicle a short distance with a manhole cover open if the tank is almost empty.
    1. True
    2. False
    Show answer
    False

    A tanker must never be driven with a valve or manhole cover open.

  18. About the emergency equipment required for your tank vehicle, you should:
    1. Assume the carrier put it on board
    2. Only check it once a year
    3. Find out what is required, carry it, and make sure it works
    4. Carry it only on hazmat loads
    Show answer
    Find out what is required, carry it, and make sure it works

    Find out what emergency equipment you must carry, have it, and be sure it works.

  19. Vapor recovery kits on a tanker should be:
    1. Removed before loading
    2. Used only in winter
    3. Kept in the cab sleeper
    4. Checked to be sure they work
    Show answer
    Checked to be sure they work

    If your vehicle has vapor recovery kits, make sure they work.