TSA liquid regulations: Essential details about the 3-1-1 rule before your airport visit

We’ve all experienced it: Standing in line at the Transportation Security Administration, only to hear the agents announce a "bag check."

Often, this is due to a passenger carrying a liquid that exceeds the permitted limit.

This process can cause delays, especially during peak travel times. Agents usually need to examine the bag, identify the forbidden item, and let the traveler choose whether to dispose of it or return it to their vehicle.

So, what are the TSA’s rules regarding liquids, and why do they matter? Most importantly, how should you pack for your upcoming journey?

Here’s a brief overview.

TSA liquid regulations: What’s the reason behind them?

The TSA's limitations on liquids originated in 2006, following a foiled terrorist plot abroad that led the agency to restrict large amounts of liquids, gels, and aerosols in carry-on luggage.

Many other nations implemented similar measures for aviation safety. You’ll encounter analogous regulations when traveling internationally — although the U.K. is working towards lifting these rules.

What exactly is the TSA 3-1-1 rule?

The TSA's restrictions on liquids—specifically large amounts—are defined by the "3-1-1 rule."

This long-standing policy specifies that:

• Liquids must be contained in bottles no larger than 3.4 ounces, or about 100 milliliters (that’s the "3").
• All bottles must fit into a single clear quart-sized plastic bag (that’s the "1").
• Each traveler is permitted only one of these plastic bags (that’s the "1").

These regulations apply to liquids, gels, and aerosol products, including items like toothpaste, shampoo, conditioner, mouthwash, and sunscreen, among others.

Liquid items exceeding 3.4 ounces need to be placed in a checked bag, including those large shampoo bottles that may only have a small amount left, according to TSA regulations.

Exceptions to the TSA's 3-1-1 rule

However, there are a few exceptions.

The TSA permits you to carry "medically necessary" liquids, gels, and aerosols in "reasonable quantities" for your flight. You must declare these items to security personnel at the checkpoint for inspection.

The TSA requests that travelers with larger quantities of medically necessary liquids take them out of their carry-on bags and place them in a bin or bowl. The agency employs various alternative screening techniques.

What items are permitted through a TSA checkpoint?

You may carry creamy cheeses, liquid chocolate, liquid coffee, creamy dips and spreads, gravy, honey, hummus, ice cream, jam, jelly, juice, syrup, peanut butter, salad dressing, sauce, salsa, soda, soup, and yogurt, provided they are in containers of less than 3.4 ounces, according to the TSA.

You can bring your water bottle with you, even if it holds more than 3.4 ounces, as long as it’s empty. This is also a great way to save money at the airport since many now feature post-security refilling stations for reusable bottles.

When uncertain, check the TSA's list of allowable items for the airport and verify with your airline.

Alternatively, consider downloading the MyTSA app. It features a "Can I Bring?" section that lets you search for items to see if they are allowed, restricted to 3.4 ounces, only permitted in checked bags, only allowed in carry-ons, or completely prohibited.