Oil and Water — Why We Dispose of Cooking Oils Instead of Draining

It’s the post-mealtime lull and you’re getting ready to clean up after cooking. Whether you’ve been grilling, sauteing, searing or stir-frying, chances are you have some leftover cooking oil sitting in your pots and pans. What are you doing with it?

You might be the Crisco-can keeper, pouring it into a metal can next to your stovetop. Maybe you wipe it off with paper towels and toss those in the trash. Or maybe, like many folks, you’re thinking of pouring that oil and grease down the drain for an easy, quick cleanup. Out of sight, out of mind, right?

Wrong.

There are some very good reasons why you should shy away from pouring cooking oils down the drain.


Some Science

As you have no doubt figured out, the fats in oils and grease are liquid when hot. As they mix with the fats and grease of the meats and other yummy stuff you’ve been cooking up, the resulting oil is liquid but very concentrated in fats. This liquid form is what pulls us into thinking that oils are fine to pour down the drain with soapy water. However, what once was liquid will run down through your pie system, mixing with other chemicals and fluids. Then, the grease and oil will cool down, and become solid; this sticky, sometimes hard substance won’t just wash away into the sea, never to be seen again. 

Add calcium from the sewers your water washes into, and you get into serious trouble. The oils and fats from your home break down into their base components of glycerol and fatty acids. When this mix with calcium, it creates a “soapy” compound that stays for a long time in the sewer system. With rain and thaw, as the water level rises, the fatty “soap” blobs cling to the sides of pipes and sewer lines, building up and becoming “fatbergs” (icebergs of fat!) that have a waxy consistency. These fatbergs backup sewers and lead to overflow and sewer water backing up into city drains.  

 

Can You Say “Clogs”?

Within your smaller home system, the resulting solid or sticky oils that have cooled off will float around and cling to the inside of your pipe system. As you continue to pour oil and grease down into the water system, the oil accumulates in your pipes, narrowing the opening and reducing the circumference of the piping. Some of the grease and oily buildup can break off and create serious clogs in your system, not to mention flow into the city sewage system, causing serious clogs. Imagine all the oil and grease as well as other chemicals, fluids and by-products all sticking together in city pipes.

 

Drainage Issues

With the diameter of your pipes reduced, water doesn’t flow and drain correctly, leading to backflow and low water pressure issues. The longer you let clogs build up, the harder they will be to clear. If you live in a building with shared plumbing, the chances are higher that issues will develop; not to mention, others who lived there before you may have been pouring oils down the drain long before you arrived! Calling in a qualified plumber is the only option. A plumber will be able to clear out the clogs and residue from pipes that are easily accessible. However, that can be a costly and complicated job.

 

Better Options

There are better ways to dispose of cooking oils than pouring them down the drain. Instead of dumping out your hot oil straight from the pan, let it cool first. Then, pour it into a resealable metal container (like a coffee can). Let the used oil accumulate until the can is full. For an eco-friendly option, bring that to a local organization that recycled used oil for biofuels.

Another option is to pour the used oil into a container with a lid (like a water bottle) and dispose of it in your trash bin. 

As for paper towels–using them to absorb oil isn’t recommended. Paper towels aren’t recyclable once they’re soiled with oil, so it’s not a very eco-friendly technique. 


For so many reasons, dumping cooking oils down the drain is a bad idea. You risk gumming up your pipes and contributing to sewer fatbergs that affect everyone in your area. Instead, dispose of your oils and grease in safer, more eco-friendly ways. If, however, your oil-disposal habits have already affected your pipes, call a trusted, experienced plumber to clean out your system.

If you’re worried about the state of your pies and want them checked out, or are having issues with clogged pipes and low water pressure, Johnson Plumbing can help. From residential plumbing to commercial systems, we do it all! Give us a shout and we’ll figure out how we can put our expertise and experience to work for you.

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