A propane tank can look full enough on a mild afternoon and become a real concern after several nights of below-zero temperatures. Knowing when propane tanks need refilling helps protect your heat, hot water, cooking, and peace of mind – especially for Montana homes where winter weather can change quickly.
The simplest answer is this: do not wait until the tank is nearly empty. Most propane customers should plan a delivery or refill when the tank reaches about 30 percent. That level leaves a practical safety cushion for weather delays, heavier-than-usual fuel use, and the fact that propane demand rarely follows a perfectly predictable schedule.
Why 30 Percent Is the Right Refill Point
A propane tank’s percentage gauge measures the amount of liquid propane inside the tank, not the vapor pressure or the strength of your appliances. A reading of 30 percent means there is still fuel available, but it is the point where waiting can create unnecessary risk.
Winter use can rise fast. A cold snap may keep your furnace running longer, while additional use from water heating, cooking, a fireplace, or a generator can draw down the tank faster than expected. Remote homes, vacation properties, and homes with long driveways may also need extra planning when snow and ice affect delivery access.
Waiting until 10 percent or less puts you much closer to a runout. It also gives your provider less room to schedule delivery around severe weather, road conditions, and other customers who need service. For a household relying on propane heat, the goal is not to use every last gallon. The goal is dependable comfort without the emergency.
How to Check Your Propane Tank Gauge
Most above-ground residential propane tanks have a round gauge beneath a small protective lid or dome. Lift the lid and look for the dial marked from 0 to 95. The number shown is the approximate percentage of propane remaining in the tank.
The gauge typically does not read 100 because propane needs room to expand as temperatures change. A tank filled to its safe capacity will generally show about 80 percent. That is normal and not a sign of a short fill.
Check the gauge at least once a month during the heating season. When temperatures are consistently cold, checking every week or two is a wise habit for customers who manage their own deliveries. Write down the reading and date if you are learning how quickly your home uses propane. Over time, that record can reveal patterns tied to weather, occupancy, and appliance use.
If your gauge is hard to read, damaged, or does not seem to change over time, call for service rather than assuming the reading is accurate. A functioning gauge is an important part of safe fuel management.
Your Tank Level Is Only One Part of the Picture
The same tank level can mean different things in different homes. A 30 percent reading in October may last quite a while. That same reading in January, after a week of subzero temperatures, may call for prompt action.
Tank size matters, too. A 120-gallon tank at 30 percent holds far less reserve fuel than a 500-gallon tank at 30 percent. The number is a useful trigger point, but your household’s rate of use determines how urgent a refill becomes.
Consider how propane serves your property. A home using propane only for a range or fireplace will consume fuel differently than a home using it for central heat, hot water, clothes drying, and a standby generator. Seasonal cabins and short-term rentals can be especially difficult to estimate because occupancy changes from week to week.
Signs Your Propane Tank May Need Refilling Sooner
The gauge is the best starting point, but a few situations deserve earlier attention. Schedule fuel sooner if a major cold front is expected, you will be away from home, or you are hosting guests during winter. More people in the house often means more hot water, more cooking, and more demand on the heating system.
You should also plan ahead if your property is difficult to access after snow. Delivery drivers need a safe, clear route to the tank. Keep the driveway plowed, mark the tank location with a visible stake, and clear a path around the tank whenever possible. Waiting until the tank is low and the driveway is buried can turn a routine delivery into a stressful situation.
For commercial properties, refill timing should account for operating hours and critical equipment. Restaurants, lodging properties, shops, and agricultural operations may have propane needs that cannot pause for a missed delivery. A written fuel plan and regular tank checks are worthwhile safeguards.
Do not use appliance behavior as your primary fuel gauge. A weak flame, a furnace that will not start, or an appliance that shuts down may have several causes, including equipment issues. If you suspect a propane problem, check the tank gauge if it is safe to do so and contact your propane provider for guidance. Do not attempt to modify regulators, valves, or gas lines yourself.
Manual Delivery vs. Automatic Delivery
Customers on will-call or manual delivery are responsible for watching their tank level and requesting fuel before it drops too low. This approach can work well for homes with stable, low propane use or owners who are consistently on site and comfortable monitoring the gauge.
The trade-off is that the responsibility remains with you. You need to account for cold weather, holidays, visitors, changing routines, and the time required to schedule a delivery. If you travel frequently or manage more than one property, manual monitoring can be easy to overlook.
Automatic delivery is designed to remove much of that uncertainty. Delivery schedules can be based on computerized degree-day tracking, which estimates fuel use from outdoor temperatures and your property’s historical consumption. Wireless tank monitoring adds real-time level information, helping a provider see when a tank is approaching the right delivery range.
For many Montana households, automatic delivery is less about convenience than protection. It means fewer gauge checks, fewer last-minute calls, and a better chance of keeping fuel available through unpredictable weather. Big Sky Propane backs monitored customers with its Guaranteed No Runouts promise, including a $500 credit if a monitored customer runs out of propane.
What to Do if Your Tank Gets Very Low
If the gauge reaches 10 percent, call for delivery right away. Reduce unnecessary propane use while you wait, but continue to use appliances normally unless your provider gives you different instructions. Never try to transfer propane from another cylinder or use an unapproved connection to stretch the remaining fuel.
If you run completely out of propane, treat it as more than a delivery issue. When a propane system loses pressure, a qualified technician must perform a leak test before gas service is restored. This safety step helps confirm that propane is not escaping from the system before appliances are relit.
Do not attempt to relight pilots or restart the system on your own after a runout. Contact your propane provider and follow its instructions. If you smell propane, leave the area immediately, avoid flames and electrical switches, and call for emergency assistance from a safe location.
Build a Refill Routine That Fits Your Property
The best refill routine depends on your tank size, appliances, family schedule, and delivery arrangement. For a primary home with propane heat, 30 percent is a strong general refill threshold. For a seasonal home, a property that sits vacant, or a business with critical fuel needs, it may make sense to schedule earlier or use wireless monitoring for more visibility.
A little planning before winter goes a long way. Confirm that your tank is accessible, learn where the gauge is located, decide who will check it, and make sure your propane provider has current contact information. If you are new to propane, ask how your tank size and appliance mix affect expected usage.
Reliable propane service starts before the tank gets low. Keeping an eye on the gauge or choosing monitored automatic delivery gives your family more than fuel in the tank – it gives you one less thing to worry about when the weather turns.