Here's How Long You Can Use Your Grill's Gas Tank Before It Becomes Illegal

Your grill's propane tank is tougher than you might think. It can stay outside all winter — provided you don't experience temps below -44 degrees Fahrenheit — and still be good to use again in the spring. However, even if your propane tank is immaculate, it does have an expiration date, of sorts, that you might not be aware of. While the propane gas does not degrade or lose any of its chemical potency over time, the tank itself "expires" after 12 years. And refilling a tank after this deadline without recertifying it is actually illegal. 

On the ring handle of the tank are a series of numbers, one of which is the manufacture date. According to the USDOT, propane tanks need to be inspected and requalified 12 years after that manufacture date. Refill attendants can't legally fill up your tank before that happens.

Besides checking the manufacture date (or last recertification) before getting it refilled, you should also inspect it for signs of wear. Obvious signs that a tank is past its usability include damage such as dents, cracks, and excessive rust. Any of these mean that your tank is beyond reasonable repair and that you should not use it under any circumstances. Using a dented or rusty propane tank isn't illegal, but checking its state is one of the fundamental safety tips you need to know before firing up your grill.

Only individuals or facilities that are registered with USDOT can perform the inspections necessary for requalification. This includes common distributors such as AmeriGas and Blue Rhino. They can perform the requalification either by external visual inspection, proof pressure test, or volumetric expansion tests. If the tank passes one of these three tests, it will then be stamped with a requalification number and date.

There may also be a letter "E" or "S" following the date. The "E" signifies that the tank was inspected externally and needs to be requalified again in 5 years. An "S" signifies the proof pressure test, which means the tank doesn't need requalification for another 10 years. If there is no letter next to the date, it means volumetric expansion has been performed, and you can requalify your tank again in another 10 years. Here's an example of what one might look like: 1026 E (i.e., requalified October 2026 by visual inspection).

Each time your tank is requalified, it will receive a new date that will tell you when it needs to happen again. As such, if you are good about keeping your grill in top shape and protect it from significant wear and tear, you can requalify your tank indefinitely.