One of the most common pieces of advice plumbers give homeowners is, "don't put grease down the drain." Perhaps you've heard this advice and taken it to heart, but many people still let grease down the drain because they don't understand why it's a bad idea. Here's a closer look at the problems caused by pouring grease down the drain, along with some advice for handling common grease-related plumbing problems.


Pouring grease down the drain causes problems in your own home as well as in public sewer systems.

Clogged Drains

Even if the grease is a liquid when you pour it down the drain, it will solidify once it hits the cool pipe walls. If you've ever tried to scrape solidified bacon fat or chicken fat out of the bottom of a pan, you know how sticky this grease can be. It will stick to the walls of your pipes in the same manner.

Some homeowners think the warnings about grease are over-hyped because they pour grease down the drain and don't immediately experience a clog. However, grease clogs don't always form immediately. What starts as a thin layer of grease can slowly grow into a serious clog as food particles stick to the grease over time. Clogs caused by grease are very difficult to remove on your own and often require the attention of a plumber.

Clogged Main Sewer Lines

Your main sewer line is the pipe that connects your home's drainage pipes to the main public sewer line that runs beneath the street. This pipe is wide, so while one day's worth of grease won't clog it, pouring grease down the drain for several months or years may eventually lead to clogs.

It's common for roots to grow into main sewer lines. While the roots themselves may not completely clog the main sewer line, they do act as a surface for grease to cling to. A clogged main sewer line can cause sewage to back up through all of your toilets and sinks. To remove the clog, your plumber may have to use a special auger to grind up the roots and solidified grease. He or she may even have to replace a portion of the sewer line.

Garbage Disposal Problems

Even if you have a garbage disposal, you should not pour grease or greasy sauces down the drain. The grease can accumulate within the grinding mechanism of the garbage disposal, causing it to seize up. At the very least, the grease accumulation will dull the blades and give off noxious odors as bacteria begin to grow.

Fatbergs in Sewers

The grease that does make it all of the way through your pipes and into the public sewer system can accumulate in large formations, which have become known as "fatbergs." These fatbergs can block drainage from numerous homes' and businesses' main sewer lines, causing serious, neighborhood-wide sewage backups. Furthermore, fatbergs are extremely difficult and time-consuming for sewer departments to clean up.


Sometimes, it's not quite as easy as just not putting grease down the drain. Here are a few more specific tips to help prevent grease problems in your plumbing.

  • When you're finished cooking, pour your grease into an old milk carton, let it solidify, and put it in the trash.
  • Write a note that says "don't put grease down the drain," and post it in front of the sink so that family members and guests know to follow this rule.
  • Always run cold water when using the garbage disposal. This step helps keep fats in your foods solid so they get chopped up and rinsed away before they can cling to your drain.
  • If your kitchen drain seems slow, use a plunger or drain cleaner to clear it before the clog gets a chance to grow any larger.

If you're afraid that your bad habit of allowing grease down the drain has begun to lead to plumbing problems, contact a plumber today. He or she can get to the bottom of the issue, whether it's a clogged drain or a seizing garbage disposal.