Skip to Content

Can You Flush Oil Down the Toilet? The Damaging Effects

We all have likely flushed various types of things down the toilet. Sometimes it is frightening when you realize that what you’ve just flushed down the toilet can cause some major trouble! What about oil?

Can you flush oil down the toilet? No, you cannot! Oil does not flush properly down the toilet. It can block your drains and will affect water treatment. Since oil can solidify, it can also cause problems with your septic tank. It is simply too risky.

Why Can’t I Flush Oil Down the Toilet?

No drain is able to handle oil, including toilets. Some of us think that toilets can handle anything, but we have to remember the destination after the flush. Since oil becomes solid in water, it causes clogged pipes.

In fact, experts have found that grease in drains ( is the top reason why sewer pipes become clogged and create backups with overflow.

Can You Flush Oil Down the Toilet

When oil comes in contact with the sewer, municipal lines can get clogged. It is an expensive mistake that is not easy to fix. You may think that the oil you use at home is insignificant compared to what is used in a commercial kitchen. However, flushing oil down the toilet even in small amounts has a significant negative impact.

It is very unlikely that you have installed a grease trap in your toilet system. Therefore, you should never flush oil down the toilet.

How Does the Oil Transform When I Flush it Down the Toilet?

When it comes to flushing oil down the toilet, you cannot think “out of sight out of mind.” Here’s what happens when you make this mistake…

When you flush oil down the toilet, it travels to the public sewage facility. In time, it will probably clog your drain pipe. The problem can be big enough to put your toilet out of commission (if you’re looking for other solutions, check out our post on Liquid Plumber)

Repairs for this sort of problem are complicated. Your drains can back up and even cause damage to your infrastructure. Think of how often you cook with oil and need to dispose of it. The frequency of oil disposal and its effects simply cause a significant negative impact.

Initially, the oil that is flushed down the toilet flows similarly to water. However, when the oil dissipates in the water it combines with other components. Sewer and septic effluents mix with the oil. The process breaks it down transforming it into larger molecule chains.

The result is a solidification of the oil. It will no longer flow like a liquid but instead becomes a sticky solid substance. This “gunk” thickens as it combines with other solid materials. The mixture transforms into what is known as fatberg (

It sounds like a science fiction story of a growing destructive monster. It infests cities around the world and can reach the size of humpback whales! Experts describe this phenomenon as a gross growing greasy glob.

This glob clogs our sewage system and can cause overflow. The clean-up is a monumental feat involving the government and utility companies. Workers have to go into the sewers to remove this material with vacuums, scrapers, and water hoses.

The problem is so significant, that even the Museum of London ( displayed a slice of a fatberg that measured 820 feet.

Now, you’ll certainly think twice before flushing any greasy substance down the toilet!

Oil Requires Proper Disposal

Oil is an essential ingredient in most kitchens. It must be properly stored, utilized, and disposed of. Discarding oil properly is necessary to protect infrastructures and the natural environment. It must be strictly kept away from drains.

Incorrect disposal of oil down drain pipes can cause expensive damage to your plumbing and sewer system. Most municipal codes prohibit disposing of oil in drains including toilets. When you need to dispose of oil, this guide will help you figure out a good plan and avoid problems.

How Can I Protect the Environment When Disposing of Oil?

The most eco-friendly choice when disposing of oil is to recycle it. Find out where oil is recycled in your area. Various services are available that take the oil to special facilities for disposal.

Oil Recycle

These special facilities break down the oil using a process of anaerobic digestion. The oil is converted into biogas that can fuel cars, generates electrical power, heats water, and performs other functions.

Used oil can also be processed into biodiesel fuel which is cleaner compared to diesel fuel. Collecting your used oil in storage containers until it can be taken to a facility is a great method.

If you don’t have an oil disposal service, you can simply collect oil in a can and dispose of the can in the garbage. It is a good habit to wipe frying pans with a paper towel before washing them. Even if it seems like a small amount of oil, it is the best practice.

Common Myths About Oil Disposal

Many myths have been passed down through generations. Here are some common ones:

It is Okay to Pour Oil Down a Drain If You Run Hot Water

It is Okay to Pour Oil Down a Drain If You Run Hot Water

This is absolutely wrong! When you run hot water when pouring oil down a drain, it only helps it travel further into the sewer line. The water will eventually cool down. The oil will still solidify and create a thick coating around the inside of the pipes.

Some Types of Oil Are Okay to Flush Down the Toilet

Any type of fat has the potential to cause a problem. Even if you think that certain types of oils won’t solidify, there’s still the potential for clogged pipes. This includes cooking grease, fats, and oils from foods like bacon, turkey, and other meats. It also includes plant-based oils such as coconut oil and others.

It’s Okay to Flush Liquid Oils Down the Toilet

This is another misconception. Liquid oils stick to sewer pipes because they float on water. They produce an oily film that can attach to solid waste such as food particles. The mixture will become a glob and create blockage in the pipes.

My Garbage Disposal Will Allow me to Put Oil Down the Drain

Garbage disposals grind solid particles of food. They are like a blender that liquefies waste before it goes down to the sewer pipes. These machines do not break down oil particles. The oil will still solidify and create a build-up that will clog your pipes.

Using Dish Soap of a Grease Cutter Will Dissolve Oil

Putting dish soap or other grease cutters in the toilet when you want to flush oil will not break down fatty particles. Dish soap and grease cutters only temporarily break down oils, fats, and grease. Eventually, deep in the sewer lines, the oil will start to thicken leading to clogs.

Smart Tips You Can Follow

Follow these tips to keep your plumbing working well:

  • When disposing of oil, allow it to cool before putting it in a can or container. Throw the container out with your trash.
  • Use a paper towel to wipe your utensils, pots, and pans before you wash them. You can also use a scraper to remove the oil before putting it in a container.
  • Never use your toilet as a garbage disposal.

So, there you have it! Flushing oil down the toilet may seem harmless, but it’s never a good idea. Contact your local municipality for resources on how to safely dispose of oils.

By practicing good housekeeping habits, you’ll ensure your plumbing stays efficient. You will also protect the health of your family and the planet.

Besides, you wouldn’t want to contribute to scary fatbergs growing across the globe!

Leave a comment

Your email address will not be published. Required fields are marked *