After you’ve finished cooking some bacon or sautéing some vegetables, it’s easy to dump the excess grease and oil down the drain without giving it second thought. It’ll just get washed away, right? Well, not exactly. Dump it in a cup, wait for it to cool, and throw it in the trash, because even a small amount of oil dumped down the drain can build up over the years and wreak havoc on not only your drainage system, but your town’s whole sewer.
Here’s what happens when you put oil down the drain: It makes its way through your pipes and gets into the sewer, where it joins up with the area’s wastewater. This wastewater can contain a wide assortment of chemicals as well as other people’s grease, and when fatty acids bond with calcium (which is common in sewer water), the two bond into a soapy, waxy compound. These little fatty blobs stick to each other as well as the walls and ceiling of the sewer, creating something that’s called a “fatberg” (yes, a fatberg). These fatbergs continue to grow and grow over time; one that weighed 130 tons was recently removed from a British sewer system and a part of it is now on display in a museum! Eventually they’ll cause water from the sewer to flow back up into your drains, which can make for a very, very bad day.
This giant, greasy mess can clearly cause a lot of damage to the sewer, but it can also clog up your pipes as well. If you’ve ever left bacon grease in the pan for too long you’ll notice that it completely solidifies as it cools and can be very difficult to clean off. Now picture this happening inside the pipes in your house, every time you rinse out your pan. Yeah, you're probably not going to want to be pouring any more grease down the drain. And while you're at it, never put these things in your microwave, either!