What's the TSA Liquid Limit?

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Packing for a Smooth Trip Past Airport Security

If your child sees her favorite strawberry bubble bath get tossed in the trash at airport security, she might have a meltdown—and if you see your pricey perfume tossed in on top of it, you might have one, too. The Transportation Security Administration is strict about how to pack liquids, gels and aerosols, thanks to a 2006 incident in which authorities discovered that terrorists were planning to bring liquid explosives on board flights leaving the U.K. You're still allowed to pack full-size bottles of these substances in your checked luggage, but all carry-on bags have to adhere to the TSA's liquid limits rule.

What Does 3-1-1 Mean?

The TSA's liquid limits rule is more commonly referred to as the 3-1-1 rule. Its name might help you remember how to pack accordingly. There are, as you might guess, three elements of the rule.

3: Each container of liquid, gels or aerosols that you pack in your carry-on must be no larger than 3.4 ounces (100 ml).

1: All your 3.4-ounce containers must be packed into a clear, resealable 1-quart bag.

1: Each passenger is limited to one bag of liquids, gels and aerosols.

Does the Rule Apply to My Kids?

Some of the TSA's rules are different for children. Kids under 12 can leave their shoes on during screening, for example. But the 3-1-1 rule applies to all passengers, even kids.

Are There Any Exceptions?

Yes! The TSA does make exceptions for people traveling with food and drinks for their infants and toddlers, and for people traveling with necessary medications.

If you're flying with a child young enough to require your assistance to walk (that's how the TSA generally decides whether kids are young enough to warrant this exception), you can bring as much juice, breast milk and formula as your child needs. Specifically, the TSA allows "reasonable quantities" of these liquids. Basically, you might encounter some pushback if an entire carry-on is packed full of juice, but it won't be a problem if you bring one or two containers per toddler intended for use during the flight.

You can keep these items cold using ice packs. However, if the packs aren't frozen solid when you arrive at the security checkpoint, they will be screened separately from the rest of your liquids. You may also bring breast milk in quantities larger than 3.4 ounces—even if you're not flying with your child.

You are required to tell the TSA that you have more juice, formula or breast milk than the 3-1-1 rule allows. Wait until you get past the ID checkpoint, and tell the first agent you see that you have milk, juice or formula for a young child. Agents will still screen these liquids to make sure they're safe.

The same exception applies to medically necessary liquids, gels and aerosols. Bring as much as you need, and inform the agents about what you have.

How Should I Pack?

The easiest way to get around the 3-1-1 rule is to pack all your liquids, gels and aerosols in your checked luggage. But if that's not possible, weed out any liquids, gels and aerosols that you can do without on your trip. If you verify that your hotel provides soap and shampoo, for instance, skip bringing those with you. Pack only truly essential things, like the specific kind of moisturizer that keeps you from breaking out. If your kids are picky about things like what kind of body wash they use, you may decide to prioritize those, too.

Buy travel versions of any items that you must have, or transfer small amounts into screw-top containers made especially for travelers. Label them with masking tape. If you're going to a destination that has plentiful convenience or grocery stores, you may even decide to just buy all new travel-sized toiletries when you arrive.

What Else Should I Know?

Although each passenger is allowed a one-quart bag, pack everyone's liquids, gels and aerosols into your bag if possible. That's because this bag has to be removed from your carry-on at security so it can be screened separately. The security area can be chaotic when you're traveling with kids. Between taking off your shoes and belt, hauling all your stuff onto the conveyor belt and keeping track of the kids, you'll have your hands full. Simplify your life by packing just one liquids bag.