20 lb Tank (4.7 Gallons) Propane Tank

About the 20 lb Tank (4.7 Gallons)

Portable use for gas grills, patio heaters, camping, and small appliances. The most common consumer propane container, available at hardware stores, gas stations, and grocery stores. Can be refilled or exchanged at thousands of locations nationwide.

The 20 lb tank (4.7 gallons) measures 18 inches tall x 12 inches diameter and has a total volume capacity of 4.7 gal. Per NFPA 58 safety regulations, propane tanks are filled to a maximum of 80% capacity to provide expansion space as the liquid propane warms and expands. This means the practical usable capacity per fill is 3.8 gal. At the national average price of $2.50 per gallon, a full fill costs approximately $9.40.

The 20 lb tank (4.7 gallons) is a portable container that can be transported in a vehicle and refilled at propane dealers, hardware stores, gas stations, and exchange kiosks. It requires no permanent installation and is the most common propane container for consumer use. Safety regulations require that portable cylinders be transported in an upright position in a well-ventilated area of the vehicle, never in an enclosed trunk or passenger compartment.

How Long Does a 20 lb Tank (4.7 Gallons) Last?

The duration between fills depends entirely on your propane consumption rate, which varies by season, appliance mix, and climate. The table below shows how long a single fill of 3.8 gal would last for four common usage scenarios at the national average baseline.

Note that the "months per fill" figure represents an average across the entire year. During winter heating months, consumption can be 2-3 times the monthly average, meaning a full tank may last only 2-3 months during peak heating season. During summer, the same tank may last 6-12 months if heating is not needed. Plan your delivery schedule accordingly, and request delivery when your tank gauge reads 20-30% to avoid running empty.

Tank Size Comparison

Compare the 20 lb tank (4.7 gallons) to other standard propane tank sizes to determine if this is the right capacity for your needs. If your annual consumption is close to the boundary between two tank sizes, choosing the larger option provides a safety margin and reduces delivery frequency.

Safety and Maintenance

Propane tanks are designed for decades of safe service when properly maintained. Above-ground tanks should be visually inspected regularly for signs of rust, physical damage, or settling of the support base. The tank should be painted with a light, reflective color (white or light gray) to minimize heat absorption from sunlight, which reduces the pressure inside the tank and decreases the risk of the pressure relief valve activating.

Keep the area around the tank clear of vegetation, debris, and combustible materials for at least three feet in all directions. Ensure the tank's pressure relief valve, fill valve, and service valve are accessible and not obstructed. Never stack items against or on top of a propane tank. If you smell the distinctive rotten-egg odor of propane (added as a safety odorant called ethyl mercaptan), leave the area immediately, do not operate any electrical switches or flames, and call your propane company and the fire department from a safe distance.

Portable cylinders like the 20 lb tank (4.7 gallons) must be recertified 12 years after the manufacture date stamped on the collar, and every 5 years thereafter. Expired cylinders cannot be legally refilled. Check the date stamp on your cylinder and exchange or recertify before the expiration date. Never attempt to modify, repair, or refill a portable propane cylinder yourself.

Frequently Asked Questions