How to Tell if a Propane Tank Is Empty

How to Tell if a Propane Tank Is Empty

Written on: August 13, 2021

propane tank level georgiaYou never want to have guests over for an old-fashioned barbecue in your backyard and have to say, “Oops, I ran out of propane” while you’re in the middle of cooking.

Since most propane portable cylinders don’t come with a built-in gauge, you need another way to figure out how much fuel is left in your tank. You obviously don’t want to wait until your grill shuts off to tell you that your propane tank is empty. (That’s why it’s best to always have a back-up propane cylinder on hand—just in case.)

3 Simple Ways for You to Try

  1. Use water. You can determine the approximate level of propane in a tank by using a little bit of water. Here’s how:
    • Fill a small bucket with hot tap water.
    • Pour the water down the side of the tank.
    • Run your hand along the side of the tank and feel for a cool spot.

    The top of the cool spot is the fill level of the tank – it’s cool because liquid propane inside the tank is absorbing the heat from the water, which makes the metal wall of the tank cool to the touch.

  2. Weigh the tank. Most propane grill tanks come with two numbers stamped on the handle – the water capacity (“WC”) and Tare Weight (TW – the weight of the tank when it’s empty). Most grilling tanks weigh about 17 pounds when empty. To measure how many pounds of propane are left in your tank, simply weigh it on a scale and subtract the TW number. For example, if a tank weighing 27 pounds has a TW of 17 pounds, there’s about 10 pounds of gas left—or about 2.5 gallons.
  3. Use an external gauge. External propane tank gauges come in several different forms
    • inline pressure gauges install between the gas line from the grill and the cut-off valve on the tank, measuring pressures to determine how full the tank is.
    • analog propane scales look like luggage scales and are pre-set to take your tank’s TW into account.
    • digital propane tank scales provide a digital readout of remaining cook time and gas fill percentage. Some even come with smart phone apps.

    Pick the device that you’re most comfortable with and give it a try!

The 80/20 Rule

When you take your portable 20-lb propane tank to a refill station or tank exchange, you should get four gallons (or 17 pounds of propane; propane weighs 4.25 pounds per gallon). For safety reasons, the propane cylinder should only be filled to 80% of its maximum capacity. Leaving it 20% empty leaves room for the LP gas to expand, which it will do when the temperature rises. A propane cylinder illegally filled to 100% capacity could burst. This same 80/20 rule also applies to your home heating propane tank.

Propane Cylinder Safety in the Aftermath of a Storm

While we’re on the topic of portable propane cylinders, this is a topical time of year to share recommended practices for the safe handling of propane cylinders that have been potentially damaged.

Natural disasters such as hurricanes and floods can result in the exposure of cylinders to a variety of hazardous conditions. This includes submersion in floodwaters, impact from flying debris, damage from falls, and exposure to foreign contaminants like mud, sewage, oil and grease.

Obviously, any damage can affect their integrity and safe operation of cylinders and related equipment. Keep in mind that the cylinder contents are stored under pressure, which can cause the contents to leak if the container or related equipment is damaged.

Cylinders that are damaged or leaking can pose serious hazards and must be addressed only by trained emergency responders with HAZMAT training or the cylinder supplier. You should never attempt to vent or even handle cylinders that you suspect have been damaged.

Contact information for the cylinder supplier is listed on the cylinder label. If a label is not present, the cylinder neck ring can be used to identify the cylinder supplier.

More Safety Tips for Propane Cylinders

Even if your propane cylinders have escaped storm damage, there are a number of safety tips you should follow year-round.

Remember: propane cylinders incorporate special components such as valves, connectors, and other parts to keep them safe for use with grills and other propane appliances. Damage to any component can cause a gas leak. Don’t risk it! Instead, contact a qualified propane service provider for assistance.

We want to make sure you know how to approach propane safety in and around your home or business, no matter how you’re using propane. We encourage you to go here to review propane safety and operation tips, courtesy of the Propane Education and Research Council.