Fatbergs: A Sewer Menace You Might Be Helping Create

My mom’s words rang in my ears: “Don’t pour grease down the drain!”

But I was in college and had no idea what else to do with the bacon grease. It was only like a tablespoon, I rationalized, so down the drain it went with some hot water.

Fast-forward several years and now I’m sitting here wondering how many fatbergs I’ve helped create in my cities’ sewers.

Wait, what’s a fatberg, you ask? In simple terms, it’s a huge hunk of oil, grease, and fat all stuck together that floats around in your city sewer.

How Fatbergs Are Formed

While it may not seem like a big deal for you to pour a little oil or grease down the drain from time to time, it becomes a major issue when everyone else in your city is doing the same thing.

When that oil or grease goes down the drain, it begins to combine with all the other oil and grease floating around in the sewer. When it all meets with so-called “flushable” wet wipes, a lethal bond is formed. Wet wipes, according to researchers, are a bit of a magnet for oil and grease. As more and more oil and grease accumulate, these blobs can become quite large. As scientists have studied these fatbergs, they’ve discovered one reason they can grow so large is the calcium in the concrete-lined sewers. The calcium combined with the oil and grease becomes soaplike in texture and sticks to the sides of the sewer.

What starts as a small buildup can cause big problems. In 2013, toilets began to overflow for some residents in London. The cause? A 15-ton fatberg that had nearly sealed off the sewer. In 2017, an even larger fatberg was discovered in Belfast. This one was composed of a couple of hundred tons of fat, oil, and grease.

The removal of these fatbergs from city sewers can cost an astounding amount. According to New York’s 2017 “State of the Sewers” report, New York City spent $18 million over five years removing fatbergs. (The problem has only increased with the pandemic as more people improperly flushed wipes — as well as disposable masks and latex gloves — down toilets.)

Fighting Fatbergs

Fatbergs have been a bigger issue in some European countries than in the United States due to various regulations. U.S. restaurants are required to have grease traps and have to dispose of their used oil in a specific way. This greatly reduces the amount of oil being sent into our sewer system.

There are, however, a few simple steps you can take to do your part in fighting off these fatbergs. First and foremost, don’t pour oil, grease, or fats down the drain. Instead, collect your oil and grease until you have a fair amount you’d like to recycle. Here’s what we recommend doing:

• Designate and label a specific container for storing your used oil. Mason jars or coffee cans work great. If you’re going to personally reuse the oil, you’ll want to keep it refrigerated.
• Once your container is filled, use the Earth911 Recycling Search to find a local recycling option in your area. If no option exists, call your local household hazardous waste facility to see if they know of a local spot. You can also try calling an area fire department to see if they collect it.
• If that doesn’t work, seal the container and dispose of it with your normal garbage. While disposing of used oil with your regular garbage is far from ideal, in some areas that’s the only option. Just make sure your container is sealed tight so the oil won’t leak.

If you’d like to learn more about recycling used cooking oil, check out Earth911’s Used Cooking Oil Recycling Guide.

Originally published on August 23, 2017, this article was updated in March 2022.