Can you Flush Oil Down the Toilet?

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After cooking a delicious meal at home, it’s tempting to flush used kitchen oil down the toilet to get rid of it quickly. But you may be wondering whether doing so is bad for your plumbing system and, if yes, what the potential consequences are.

Is it OK to Flush Oil in Toilet?

Cooking oil is not supposed to go down into the sewers or septic tanks. A bit of it in the sink drain after frying something might be Okay, but pouring ounces of leftover oil in the toilet and flushing it regularly for quick disposal creates unnecessary plumbing emergencies that may cost you a lot in repairs or replacements. Along with the headaches that come with these issues, you’ll seriously harm the environment in the process. 

What Happens if I Flush Oil Down the Toilet?

Pipe Blockages

When hot oil cools, it sticks to the inside of the toilet drain pipes and hardens. Over time, more and more build-up of oil narrows the plumbing pipe, which leads to less water flow and, eventually, you end up with a complete blockage.

You may have some success clearing the clog by using a plunger. However, this won’t last long. Clearing blocked pipes often requires you to contact professional plumbing services, which can cost a lot. 

Oil in toilet drain pipes can also reduce the lifespan of your home’s plumbing system. Constant build-up and the need for frequent unclogging or repairs can lead to earlier than expected wear and tear. You’ve only left with one choice here: replace the pipes, pay the high price, and deal with the mess that goes with it. 

Fatbergs & Sewer Backups

One of the most notorious consequences of flushing kitchen oil and other fats is the formation of fatbergs. Never heard of it? They are large clumps of fat, oil, and other non-biodegradable materials like wet wipes and sanitary products that are soft at first but turn to solid.  

Fatbergs can grow to huge sizes and have the potential to completely choke sewer pipes. This causes backups, where wastewater flows back into homes. Along with this problem, you have to now deal with foul odors and damage to property. Cleaning up after a sewer backup is not only frustrating and requires professional help but can also be expensive and time-consuming.

Infestation & Health Hazards

Oil flushed down the toilet drain creates a sticky residue on your sewer system that can trap other food particles and organic matter. When this residue builds up, it causes blockages or slows down the flow of wastewater, which is an ideal feeding ground for rodents, insects, and other vermins. 

Once these pests find a steady food supply, combined with moist and warm conditions in the sewer lines, they are likely to nest and multiply. That makes your home prone to infestation. 

There’s more to it!

Rodents and insects may carry bacteria and diseases, which can potentially contaminate your home if they enter through the plumbing. This affects your water supply and living environment, which gives rise to major health concerns for you and your family.

How to Get Rid of Oil?

Instead of pouring used kitchen oil into the toilet and flashing it, you can get rid of it in any one of the following ways:

  • Paper Towel: Use paper towels to wipe the pan after sauteing something, toss them in the trash, and wash the pan with hot water. But make sure washing doesn’t ruin the pan’s seasoning, which is a common problem with cast iron brands. 
  • Cool and Solidify: Let the excess oil cool down completely. Now, pour it into a disposable container (like an old milk carton or plastic bottle) that can be sealed, and then dispose of it with your regular trash. This ensures the oil does not leak or spill during transportation.
  • Local Regulations: You might be living in an area where used cooking oil is considered hazardous waste. Contact the local waste disposal authorities, ask them if they have particular guidelines in place, and follow them to the letter.
  • Reuse: Oil does not need to be disposed of every time. You can actually save it in heavy plastic jugs or other containers, cool it down to room temperature, and reuse it the next time you deep/pan fry. 
  • Recycle: Many communities have recycling programs that are willing to accept used cooking oil. You can simply collect it in a container for a couple of weeks or a month and give it to them.


If you are in the habit of flushing cooking oil down the toilet, it won’t do you any good. You’ll face major plumbing issues like clogged or damaged pipes, which are usually costly to repair and replace with professional help. When oil enters the sewer system and builds up gradually, it gives you more plumbing problems with complete blockages, resulting in backups.

Always get rid of the kitchen oil in the right way to protect your plumbing that saves you thousands of dollars down the road.