This Is the Worst Thing to Pour Down the Drain, According to an Expert

When we cook, grease often accumulates from the fats and oils in the ingredients we heat up. This happens when we cook with oil, butter or fatty foods such as ground beef or bacon. This grease in the bottom of the pan may leave you wondering what you should do with it.

If you’ve thought about disposing of it in your kitchen sink, Joe Mouawad, general manager of Eastern Municipal Water District, sternly recommends you don’t.

“Fats, oils and grease (FOG) are incredibly harmful to our wastewater collection system,” he says. “When FOG is poured down your drain, it quickly hardens and causes blockages in the system.”

This type of blockage can wreak havoc on your pipes, and it’s extremely common. According to New York City’s 2019 State of the Sewers report, 66% of sewer backups were determined to be caused by grease.

When grease from multiple pipes builds up, it can also cause something that UK sewage treatment company Thames Water dubbed “fatbergs.” Think icebergs, but instead of being made up of ice, a fatberg is fat, grease and garbage (frequently wipes) that become trapped in sewage drains after being disposed of through pipes. In 2017, Thames Water shared a video of an 820-foot, 130-ton fatberg in a sewage system, which took weeks and millions of dollars to remove, as reported by the BBC.

Because of the multitude of issues that built-up grease can cause, experts warn against ever pouring any amount of it down the drain. Here’s everything to know about safely disposing of cooking grease.

Why is pouring cooking grease down the drain so harmful?

Though grease may go down your drain in liquid form, the problems occur once it cools and hardens, which will cause blockages in your home’s sewer pipes and even “the main pipelines under the street,” Mouawad says.

These specific types of blockages are “very difficult to clear out and it blocks the flow of wastewater through the system,” Mouawad adds. “If wastewater is blocked from flowing through the system, it can back up, sometimes resulting in a costly fix inside your home.”

Once the grease is hardened in your pipes, it can also form a “sludge” that continues to grow as additional liquids and food particles go down the drain.

“A FOG clog can lead to a sewage backup not just in your home, but also outside, where it can contaminate bodies of water,” Mouawad says.

How to dispose of cooking grease

Because cooking grease hardens when it cools, you can pour the grease into a disposable container, such as a can, jar or takeout container, and wait for it to harden, then throw it in the trash. And, no, cooking grease, lard and excess oil can’t be composted.

Alternatively, you can strain any food particles from the grease and store it in the refrigerator for future use while cooking.

Read more: How to Use Leftover Bacon Grease Like a Pro

What to do if you accidentally pour grease down your drain

If you inadvertently pour grease down your drain, Mouawad says, you must take “immediate action.”

“Rinse the drain with very hot water mixed with a generous amount of degreasing dish soap to keep it from solidifying,” he says.

Keep in mind, however, that this isn’t a permanent solution and that you shouldn’t think of it as a way to keep pouring grease down the drain.

“If you continue pouring FOG down the drain, no amount of degreasing is going to save your pipes,” Mouawad says. “Eventually you will be forced to call in a professional to see how much damage has been done. This can be a costly problem and one that affects other systems throughout your home.”