What to Do with Old Lawn Mower Gas?

The warm summer air is calling, and your lawn mower is itching to get back to work. But before you fire it up, you might be staring down a container of old gas—that pungent, murky liquid that’s been sitting in your shed for months (or maybe even years). What’s a responsible homeowner to do with this hazardous material? This article will delve into the dangers of old gas, explore safe and environmentally-friendly disposal options, and provide tips for preventing this problem in the future.

In short, dumping old lawn mower gas down the drain or on the ground is a big no-no. It’s harmful to the environment and could even lead to legal trouble. So, what are your options? Let’s explore them.

The Perils of Old Gas

Old gasoline isn’t just a smelly nuisance; it’s a potential hazard. Here’s why:

1. Evaporation and Volatile Organic Compounds (VOCs)

Gasoline is made up of volatile organic compounds (VOCs), which readily evaporate into the air. As gas ages, these VOCs evaporate faster, releasing harmful chemicals into the atmosphere. These VOCs contribute to smog, acid rain, and climate change.

2. Water Contamination

Old gas can seep into the ground, contaminating groundwater and soil. This can harm plant life, wildlife, and even our drinking water.

3. Fire Hazard

Old gas can become unstable and more flammable. It can easily ignite, causing fires and explosions.

4. Engine Damage

Using old gas in your lawn mower can lead to engine problems, including:

  • Clogging: Old gas can leave gummy deposits in your engine, clogging fuel lines and carburetor parts.
  • Reduced Performance: The decreased volatility of old gas can make it difficult for your engine to ignite properly, resulting in poor performance and reduced power.
  • Corrosion: The chemical composition of old gas can corrode engine components, causing damage and costly repairs.

Safe and Responsible Disposal Options

Now that we understand the dangers of old gas, let’s explore safe and environmentally-friendly disposal options:

1. Local Hazardous Waste Collection Events

Many communities organize regular hazardous waste collection events where you can safely dispose of old gas and other hazardous materials. Check with your local government or waste management agency for upcoming events in your area.

2. Certified Hazardous Waste Facilities

If there aren’t any collection events scheduled, you can search for certified hazardous waste facilities near you. These facilities are equipped to handle hazardous materials safely and responsibly. You can find a list of certified facilities on the EPA’s website or by contacting your state environmental agency.

3. Gas Stabilization Products

While not a complete solution, gas stabilization products can help extend the life of your fuel by preventing the formation of harmful gums and varnish. However, these products don’t remove the need for responsible disposal eventually.

Preventing Old Gas: Tips for Responsible Storage

The best way to deal with old gas is to prevent it from accumulating in the first place. Here are some tips for responsible gas storage:

1. Use Fresh Fuel

Always use fresh gas in your lawn mower. Try to avoid storing gas for more than 30 days, as it will start to degrade.

2. Store Gas Properly

  • Sealed Containers: Store gas in airtight, approved gas cans to minimize evaporation.
  • Cool, Dry Place: Store gas cans in a cool, dry place away from direct sunlight. Heat and humidity accelerate the degradation process.
  • Label Clearly: Label your gas cans clearly with the type of fuel and the date it was purchased. This will help you keep track of its age and prevent accidental misuse.

3. Empty Your Tank Before Storage

Before storing your mower for an extended period, drain the fuel tank and run the engine until it stops. This will help prevent the gas from degrading and causing problems when you’re ready to use your mower again.

A Final Thought

While disposing of old gas may seem like a chore, it’s an important step in protecting our environment and ensuring the safe operation of your lawn mower. By following these tips, you can responsibly manage your gas and avoid the potential hazards associated with old fuel. So, next time you’re putting your lawn mower away for the season, remember to take care of that old gas, and your lawn, your wallet, and the environment will thank you for it.


1. Is it safe to pour old lawn mower gas down the drain?

No, it’s definitely not safe to pour old lawn mower gas down the drain. Gasoline is a hazardous substance that can contaminate water sources and harm wildlife. It can also damage your plumbing system. Instead of pouring it down the drain, you should dispose of it properly.

There are safer ways to dispose of old gas, such as taking it to a local hazardous waste facility or using a gas treatment product. If you have a small amount, you can also mix it with sand or cat litter to absorb it and then dispose of it in the trash.

2. Can I use old lawn mower gas in my car?

It’s not recommended to use old lawn mower gas in your car. While your car might run on it, old gas can cause problems with your engine. The fuel may have lost its volatility and could lead to poor engine performance, starting difficulties, and even damage to your fuel system.

It’s best to stick to fresh gasoline for your car and use the old gas for your lawnmower or other small engines. However, if you have a small amount of old gas, you can try adding a fuel stabilizer to it to help extend its shelf life.

3. How long can I store lawn mower gas?

Gasoline can degrade over time, even if it’s stored properly. If you store it in a sealed container, it can last for a few months, but it’s best to use it within a year.

After a year, the gasoline will start to lose its volatility, making it difficult to start your lawnmower. It can also gum up the fuel system, leading to problems with your engine.

4. How can I prevent old lawn mower gas from forming?

The best way to prevent old gas from forming is to use it regularly. If you don’t use your lawnmower often, you can store the gas in a sealed container with a fuel stabilizer. Fuel stabilizer helps to prevent the gas from degrading and extends its shelf life.

Make sure to store the gas in a cool, dry place and avoid storing it in direct sunlight. It’s also a good idea to label the container with the date you filled it so you know how long it has been stored.

5. Can I add old lawn mower gas to new gas?

It’s generally not a good idea to add old lawn mower gas to new gas. Even if the old gas doesn’t seem to be causing problems with your lawnmower, it could contain impurities that can harm your engine.

If you have a small amount of old gas, you can add it to a larger quantity of new gas. However, this is not recommended if the old gas is more than a year old.

6. What are some signs that my lawn mower gas is too old?

There are a few signs that your lawn mower gas is too old. The gas might have a strong, pungent odor, it may be discolored, or it may have a gummy residue. You might also notice that your lawnmower has trouble starting or running.

If you see any of these signs, it’s best to drain the old gas and replace it with fresh gas.

7. Is it better to use ethanol-free gas in my lawnmower?

Ethanol-free gas is a good choice for lawnmowers and other small engines. Ethanol can absorb moisture from the air, which can lead to corrosion and other problems with your engine.

Ethanol-free gas is more stable and can last longer than gas with ethanol. If you don’t use your lawnmower often, using ethanol-free gas can help to prevent problems with the fuel system.

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