How is Whole House Generator Fuel Stored?

generator fuel

A major component of being a responsible generator owner is having fuel on deck. Your generator cannot run without fuel. So, it’s essential that you are storing generator fuel. Because you cannot predict when a power outage will strike, you never know when you’ll need to break out the fuel to power your generator. So, sometimes you will have to store fuel on a long-term basis. This means you must take precautions to maximize the storage life of your generator’s fuel. In this guide, we’ll walk you through all the steps that go into properly storing your whole house generator fuel.

Table of Contents:

Storing Whole House Generator Fuel

This may surprise you, but gasoline has a short shelf life. After only a few months, the components in gasoline can break down. Using gasoline which has destabilized may actually damage your generator and prevent it from starting. In fact, many manufacturers of engines used in generators put restrictions on the amount of time gasoline should be stored before use in engines. Be sure to consult with the restrictions you find on your generator.

Generally speaking, gasoline should be kept in a cool area and the container should be kept almost 95% full. You should leave that 5% space just in case the gasoline needs to expand. You, also, don’t want to store fuel inside of your generator, especially if it’s a gas-powered unit. In fact, the general consensus is that plastic fuel cans are the best method for storing fuel. Moreover, gasoline is a dangerous substance so it should NOT be stored in your house, especially in large quantities. The National Agricultural Safety Database actually has some tips on how gasoline should be stored:

  • Gasoline should be stored in a well-ventilated area separate from the house.
  • The location should have no electrical equipment, open flames, or other sources of ignition present.
  • The location should be protected from the heat of the sun to keep evaporation to a minimum.
  • If you do not have a suitable storage area, consider building a cabinet outside your house for storage or purchasing a commercially available flammable liquid storage cabinet, available from safety equipment suppliers.

What you should note is that if the gasoline will not be used right away, will be exposed to direct sunlight, or will be stored at temperatures above 80 degrees Fahrenheit, you should add a fuel stabilizer/additive. A good fuel stabilizer can double and even triple the viable life of the generator fuel you’re storing. For example, you can purchase “Sta-Bil” which is a common additive for gasoline.

To continue, the storing specifications may change depending on what type of fuel you are utilizing. Let’s a take look at the storing guidelines for a few fuel types:


When it comes to generators, diesel is typically favored over gasoline. Diesel has a much longer shelf life than gasoline. Diesel fuel can last up to a year without any additives, depending on the storage conditions. For diesel to have maximum shelf-life, it needs to stay dry and be stored at a cool temperature (less than 70 degrees F). Exposure to water, air, and heat will shorten that shelf life. Diesel fuel should only be stored in a container or tank made specifically for the use of diesel. 


Unlike gasoline and diesel, propane does not degenerate over time, so it virtually has a limitless shelf life. Still, the integrity of propane has much to do with the tank it is stored in. If the tank falls into disrepair, the propane may be lost. When you install a propane generator, you will need to choose the size of the propane tank to purchase. For whole house generators, you’ll most likely need a 100-gallon or 500-gallon propane tank. It is vital to follow government regulations on the installation and placement of these tanks. Still, it is highly important to stay alert for any potential leaks and to never expose the tank to more than 120-degree F.

Natural Gas

If you have a natural gas generator, the gas is supplied to your home through underground pipes. In this case, you need not worry about storing fuel. However, beware of any natural gas leaks. Such a leak can lead to the risk of carbon monoxide poisoning.

How Does Storing Portable Generator Fuel Differ?

Storing fuel for a portable generator does not differ all that much from storing fuel for a whole house generator. Out of the few differences, the biggest is that portable generators require less fuel. So, portable containers typically hold five gallons or less. Again, you shouldn’t fill the containers completely. Fill each container with no more than 4.75 gallons of fuel to allow for gas expansion. The container may split or burst if the gas expands too much with no room. Containers should be kept away from gas water heaters, furnaces, and other sources of flame. The best place to put fuel containers is in the garage, shed, or other well-ventilated area. Don’t store containers directly on concrete since it may cause the container to deteriorate. Once again, a gasoline stabilizer can be useful for long term storage. It can extend the shelf life from 2-4 months to 12 months.

What are the Costs Associated?

On average, whole house generators can cost anywhere from $5,000 to $25,000, depending on your home size and energy needs. About 60% to 70% of the total project cost is just for the unit itself and does not include the fuel tank needed to power the generator. The cost of your whole house generator can change in subject to the type of generator you are purchasing.

Natural gas generators cost around $2,000 to $21,000 for home models. They don’t require fuel storage because they connect to the utility grid. Propane generators cost about $2,000 to $21,000 for home models. They are a good option for off-the-grid and rural areas where no natural gas lines may exist. Diesel generators cost around $3,000 to $20,000. They are larger units, but they generate a lot of power and are known for their efficiency. However, you’ll have to worry about high fuel costs.

What About Commercial Generator Fuel Tanks?

When it comes to commercial sites, diesel-fueled generators are the go-to as a source of primary power and emergency back-up power. If there is a power supply failure, it is highly important that there is an adequate amount of fuel and that it is stored correctly. Here are a few tried and true methods of storing commercial generator fuel tanks:

  • Burying the tank underground: This method of fuel storage is a great space saver when the tank needs to be installed in a tight location. However, the installation process is complex and even when completed, there needs to be ongoing monitoring and maintenance.
  • Placing tanks in a fire-rated room: A fire-rated room is essentially a room that is designed to protect the tank inside it from fire and other major hazards. The walls, roof, and all penetrations in and out of the room will need to have a fire resistance level (FRL) of 240/240/240. This means that this room and any building element must be able to withstand a fire for 240 minutes with respect to three criteria: structural adequacy, integrity, and insulation. Fire-rated ventilation/dampers will also need to be installed. A removable roof for tank replacement will need to be designed and installed, as well as a fire-rated door that is designed to stay closed. 
  • Installing an above-ground fire-rated tank: This method of storing diesel for your generator is becoming the simplest and most cost-effective way to store fuel. With a fire-rated tank, it is important that the structural adequacy, integrity, and insulation are demonstrated on the complete tank. Only a 4-hour fire-rated would be deemed equivalent to an FRL of 240/240/240. A 4-hour fire-rated tank may store flammable or combustible liquids inside or close to a regular building.

Contact A&J Generator & Equipment to Install Your Standby Generator!

Now that you know how to properly store your fuel, you can go out and invest in your generator. When you find the right generator, do not hesitate to contact A&J for installation. We install and specialize in propane, natural gas, and diesel generators. Ready to get started? Reach out today!

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