What You’ll Learn
Is it bad if I let my propane tank drop below 20%?
Yes. At 20%, you’re not in immediate danger—you still have a few days of fuel.
But below 10%, safety risks increase: air can enter the system, rust can form, and leaks may go undetected.
Most suppliers require a certified safety check before refilling an empty tank, which adds time and cost.
In this blog:
This blog was updated March 2026.
Don’t let your propane gauge hit empty.
You probably don’t spend much time thinking about your propane tank levels. By the time you think to check your propane tank gauge, you’re at 20%, in danger of dipping into that angry-looking red section.
Don’t worry—you are not in trouble quite yet. But this is your sign to reorder, since you don’t want your tank to be below 20% full.
So what does happen if you let the propane gauge dip below 20%? We’ll get to that. But first, you need to understand how your propane tank works. Read on to learn more about home propane tank care.
How Does Propane Work?
Propane (also called LP gas or LPG-liquefied petroleum gas) is widely used to fuel heating, refrigeration units, generators, BBQs, and appliances.
It is transported and stored in thick-walled steel containers as a very cold, pressurized liquid. Liquid propane expands into gas inside its tank.
Safety First: Understanding Propane’s Properties
Propane is naturally non-toxic, colorless, and odorless. An odor compound is added to make propane easier to detect in the event of a leak or spill.
Propane gas vapor is heavier than air and can collect in low areas such as basements, floors, and crawl spaces.
Propane is highly flammable when mixed with oxygen. Watch out for ignition sources, such as unshielded flame, smoking materials, electrical sparks, and static electricity.
For this reason, propane tanks and their filling ports are generally located outdoors so that vapors may dissipate.
Your Propane System & Propane Tank Gauge
Become familiar with the different parts of your propane system. Quick action may be needed in the event of a leak or other emergency.
If you have an underground storage tank, only the cover will show above ground. This cover protects the shut-off valve, pressure regulator, pressure safety release valve, and propane gauge.
Propane is delivered as a pressurized liquid. It is pumped into a specially-designed, thick-walled storage tank. Liquefied petroleum gas changes to a gaseous form before it leaves the tank.
Propane leaves the tank via underground pipes to your boiler, furnace, or appliances.
Key Components: Regulators, Valves, and Connectors
You may also have a second pressure regulator at the point where the gas line enters the structure.
If your gas comes out of your tank at excess pressure, the pressure regulator kicks in and prevents the pressure from damaging your equipment. There should be a manual shut-off valve for each appliance to stop gas flow.
The final segment of the gas pipeline is the flexible connector that attaches the appliance to the fixed pipes. This short connector allows the appliance to be moved without disconnection for service or cleaning. Inspect the connector for leaks or cracks whenever you clean around and under it.
Understanding Propane Tank Levels
Propane tanks are heat sensitive. Too much heat forms high pressure inside the tank.
Above ground, tanks are painted white or silver to reflect heat.
In cold weather or when the tank is too empty, the gases do not expand enough to fill the tank’s volume. This results in low pressure.
There are serious safety hazards to running out of gas. Fire or explosion is among the most serious.
Really? Explosion? How does that happen?
- Valves or gas lines are left open when the gas runs out, and refills leak out
- Air and moisture cause rust in an empty or nearly empty tank, and that weakens the tank
- Rust removes the odor from propane, and leaks go unnoticed
All it takes is stray gas vapor to reach an ignition source, and fire or explosion can result.
Less distressing, but no less inconvenient, is the process to recharge a tank that has gone empty.
- Pilot lights on all appliances go out and must be restarted
- Check for leaks before restarting.
For your safety, many states require a qualified service technician to perform a leak check before restarting pilot lights. This can be both costly and time-consuming.
What Happens if I Let the Propane Gauge Go Below 20%
If your propane tank gauge is at 20%, don’t panic. While this indicates it’s time to reorder, you likely have a few days’ worth of propane left. Be sure to call your propane supplier to schedule delivery and avoid running out.
If possible, reduce your propane usage until your tank is refilled. Do not let your pilot lights go out if you can avoid it. If your propane tank gauge dips below 10%, your technician must perform a safety check, which may result in an additional charge.
Delivery Delays and What to Do While You Wait
A good propane company will do its best to schedule your delivery right away. Just be aware that you may have to purchase a minimum number of gallons and/or pay a higher price for fewer gallons.
If you must burn alternative fuels while you are waiting for propane, take the time to close all propane valves. Ventilate your area thoroughly. Incomplete fuel burning, especially wood or coal, can fill your space with dangerous carbon monoxide and soot.
To Avoid Emergency Delivery of Propane
Keep an eye on your propane gauge. Some people find it helpful to make a habit of something simple, like putting on socks, then glancing at the gauge. Others prefer regular reminders sent to their mobile phones. You can even get remote monitoring gauges that will phone or text you at certain preset levels.
Always plan on delivery at 20% or so.
Set up a regular delivery schedule with your dealer. Many dealers have a regular route. There may be a minimum delivery size. For the best prices, try to avoid calling for fuel during a cycle.
Know the parts of your propane system and keep your appliances in good repair. Efficient propane burning leaves almost no residue or pollution. A well-maintained system uses less fuel than one that gets no service.
Never Run Out of Propane Again
A few seconds of checking your gauge can save you from days without heat.
Become a Kauffman Gas customer today and enjoy automatic delivery, tank monitoring, and peace of mind. When you switch, you’ll also receive a gallon-for-gallon credit for up to 200 gallons from your current provider.
FAQs
What happens if the propane gauge drops below 20 percent?
When your propane tank hits 20 percent, it’s time to reorder.
You still have a few days of propane left, but you should schedule a delivery to avoid running out.
Try to reduce propane usage until your tank is refilled, and avoid letting your pilot lights go out.
What happens if the propane gauge goes below 10 percent?
If your tank falls below 10 percent, a safety check is usually required before refilling. This can add extra cost.
Many suppliers also require a minimum delivery amount when a tank is this low, which may increase your total bill.
What causes propane levels to drop faster than expected?
Propane levels may fall more quickly due to cold weather, leaks, appliance malfunction, or rust inside the tank.
Cold temperatures lower tank pressure, which can show a falsely low reading. Leaks and pilot lights going out can also cause unexpected usage.
Why is a propane leak check required when a tank goes empty or is very low?
When a tank runs out or becomes extremely low, air enters the system.
A certified technician must perform a leak check before restarting the system to ensure there are no leaks and that all appliances can be safely relit.
How can I avoid running out of propane?
You can avoid outages by checking your gauge regularly, setting reminders, enrolling in automatic delivery, or asking your supplier about tank-monitoring options.
Reordering propane when you reach 20 percent helps prevent emergency service calls.
What should I do while waiting for a propane delivery if my tank is low?
Reduce propane usage, keep appliances off when possible, close any unused propane valves, and ventilate your area thoroughly.
Avoid operating propane appliances if your tank is near empty, because low pressure can affect performance.
Is it dangerous to let my propane tank run out completely?
Yes. An empty tank can allow air and moisture into the system, which increases the risk of corrosion, leaks, and malfunctioning appliances.
It also requires a mandatory safety leak check before the tank can be refilled.