The F endorsement lets you haul liquids and gases in tank vehicles on Tennessee roads

The F endorsement on a Tennessee CDL authorizes you to operate tank vehicles — trucks with permanently mounted tanks that carry liquids or gases. Without it, you cannot legally drive a tanker truck for commercial purposes, even if you hold a valid CDL in another class. The endorsement applies to any tank vehicle with a capacity of 1,000 gallons or more.

You need the F endorsement whether you are hauling milk, fuel, water, chemicals, or compressed gas. The cargo does not have to be hazardous for the endorsement to be required — the tank itself is what triggers the rule. If the tank is permanently attached to the vehicle frame and holds 1,000 gallons or more, you need an F on your license.

Tennessee issues the F endorsement only after you pass a written knowledge test specific to tank vehicles. The test covers tank vehicle handling, weight distribution, surge and slosh effects, and safe braking practices. You take the test at a Tennessee Driver Services office, and you must pass before the endorsement is added to your CDL.

Key Takeaways

  • The F endorsement is required to operate any tank vehicle with a capacity of 1,000 gallons or more in Tennessee, regardless of the cargo type.
  • You must pass a written knowledge test at a Tennessee Driver Services office; the test covers tank vehicle dynamics, braking, and cargo movement.
  • If you already hold a CDL in Tennessee, you can add the F endorsement without retesting for your base class.
  • Tank vehicles handle differently than other commercial trucks because of surge and slosh, which the test ensures you understand.
  • You cannot legally haul cargo in a tank vehicle without the F endorsement, even if you have a CDL in another class.

Who needs the F endorsement in Tennessee

Any driver operating a tank vehicle commercially in Tennessee must have an F endorsement. This includes drivers hauling fuel, milk, water, food-grade liquids, chemicals, and compressed gases. The endorsement is required even if you are hauling non-hazardous materials — the size and type of vehicle, not the cargo, determines the requirement.

If you drive a tank vehicle as part of your job and you do not have an F endorsement, you are operating illegally. Law enforcement can cite you, and your employer can face fines. Insurance may also deny claims if an accident occurs while you are driving without the required endorsement.

Owner-operators and company drivers both need the endorsement. If you own a tank truck or drive one for a carrier, you must have the F on your CDL before you operate it on public roads.

How to add the F endorsement to your Tennessee CDL

Start by visiting a Tennessee Driver Services office in person. You cannot add an endorsement by mail or online. Bring your current CDL, proof of Tennessee residency (utility bill, lease, or bank statement dated within 60 days), and payment for the endorsement fee. The fee varies but is typically under $20; call your local office to confirm the exact amount.

At the office, tell the clerk you want to add an F endorsement. They will give you the tank vehicle knowledge test. The test has 20 questions, and you must answer at least 16 correctly to pass. You have one hour to complete it. If you fail, you can retake it the same day or return another day at no additional fee.

Once you pass, the office adds the F endorsement to your CDL on the spot. Your updated license will be printed and issued when ready. If you fail the test, ask the clerk for study materials or a list of topics covered so you can prepare for your next attempt.

What the tank vehicle knowledge test covers

The Tennessee tank vehicle test focuses on how liquids and gases move inside a tank while the truck is moving, stopping, or turning. You will answer questions about surge (the forward and backward movement of liquid when you accelerate or brake) and slosh (the side-to-side movement when you turn). Both effects make tank vehicles harder to control than other commercial trucks.

The test also covers proper braking techniques for tank vehicles. Because the liquid inside shifts weight, braking distances are longer and the truck is more prone to jackknifing. You will be asked about safe speeds, following distances, and how to brake smoothly to prevent cargo movement.

Other topics include weight distribution, how to inspect a tank vehicle before driving, and safe procedures for loading and unloading. The test assumes you already know how to operate a commercial vehicle — it tests knowledge specific to tanks. Study materials are available at Tennessee Driver Services offices or online through the Tennessee Department of Safety and Homeland Security website.

F endorsement costs and timeline

The endorsement fee is a one-time charge, typically under $20, paid when you take the test. There is no separate process fee. If you fail the test, you can retake it at no additional cost on the same day or at your next visit.

The entire process takes about 30 minutes to an hour at the Driver Services office. You take the test, receive your results when ready, and if you pass, your updated CDL is printed and issued the same day. There is no waiting period or mail processing — you leave with the endorsement in hand.

If you fail the test, you can study and return whenever you are ready. There is no important date or limit on how many times you can retake it. Most people pass on their first or second attempt if they study the tank vehicle topics beforehand.

Differences between F and other tank-related endorsements

Tennessee uses the F endorsement for all tank vehicles. Some states have separate endorsements for hazardous materials tanks, but Tennessee does not. If you are hauling hazardous materials in a tank, you need both the F endorsement and the H endorsement (hazmat). The H endorsement requires a federal background check and fingerprinting through the Transportation Security Administration (TSA); the F endorsement does not.

The F endorsement is also different from the N endorsement, which covers tank vehicles that carry hazardous materials that require placarding. If you haul hazmat, you need the H. If you haul non-hazmat in a tank, you need only the F. If you haul hazmat in a tank, you need both F and H.

Do not confuse the F endorsement with a tanker endorsement in other states — Tennessee calls it the F. The knowledge test and requirements are the same across states, but the letter designation varies.

What happens if you drive without an F endorsement

Operating a tank vehicle without an F endorsement is a violation of Tennessee commercial driving regulations. Law enforcement can stop you and cite you for driving without the required endorsement. The citation carries a fine and may result in points on your driving record.

Your employer can also face penalties if they knowingly allow a driver to operate a tank vehicle without the endorsement. Insurance companies may deny claims if an accident occurs while you are driving illegally. If you are involved in a crash while operating without the endorsement, liability could fall entirely on you or your employer.

If you already have a CDL and drive tank vehicles, adding the F endorsement is straightforward and inexpensive. It takes one office visit and one test. The risk of operating without it is not worth the small effort required to obtain it.

Frequently Asked Questions

Can I add the F endorsement if I do not have a CDL yet?

No. You must hold a valid CDL first. If you do not have a CDL, you need to obtain your Class A or Class B CDL through the standard testing process, then add the F endorsement. You cannot get the F endorsement on its own.

Do I have to retake my CDL test to add the F endorsement?

No. If you already have a valid Tennessee CDL, you only take the tank vehicle knowledge test. Your existing CDL class and other endorsements remain unchanged. You do not retake the general knowledge test or the road test.

How long is the F endorsement valid?

The F endorsement is valid for the same period as your CDL. In Tennessee, a CDL is valid for eight years. When you renew your CDL, the F endorsement renews with it at no additional cost unless you are renewing early or changing your address.

What if I fail the tank vehicle test?

You can retake the test when ready or at your next visit to a Driver Services office. There is no waiting period between attempts and no additional fee for retakes. Most people pass after studying the tank vehicle topics for a few hours.

Do I need the F endorsement to haul water or milk in a tank?

Yes. The F endorsement is required for any tank vehicle with a capacity of 1,000 gallons or more, regardless of whether the cargo is hazardous. Water and milk are non-hazardous, but you still need the F endorsement to legally operate the tank vehicle.