Kitchen Sink Keeps Clogging? Why Grease Is the Cause

Published November 4, 2026 · By Richie Williams

If your kitchen sink keeps clogging, the cause is almost always grease coating the inside of the drain line, and a snake only opens a small hole through it. Hydro jetting cleans the full width of the pipe, which is why it stops the clog from coming back. Here is how to tell if that is what you are dealing with.

Why does my kitchen sink keep clogging?

Bathroom drains usually clog with hair, which forms a plug in one spot. Kitchen drains clog with grease. Fats, oils, and food residue go down the drain warm and liquid, then cool and stick to the inside of the pipe. Layer by layer, the opening gets narrower until food scraps and soap catch on it and the water backs up. That is a different problem from a single blockage, and it needs a different fix. For the other common causes, see why a drain keeps clogging.

Why does snaking only work for a few weeks?

A drain snake punches a hole through the blockage so water can flow again. That works well for a single clog. With grease, the snake opens a narrow channel through the middle and leaves the coating on the walls. The line is still mostly closed, so it clogs again, usually within weeks. If the same kitchen drain has been cleared more than once this year, that is the pattern. Here is the full comparison of hydro jetting vs. snaking.

How do I know grease is the problem?

• The kitchen sink clogs again within weeks or months of being cleared
• Water drains slowly even right after a cleaning
• You hear gurgling or notice a sour smell coming from the drain
• The dishwasher backs up into the sink
• Other drains on the same line start slowing down too

Two or more of these together almost always means grease along the line, not something stuck in the trap under the sink.

What actually fixes a grease clog?

Hydro jetting sends water through the line at very high pressure, strips the grease off the pipe walls, and flushes it out to the sewer. Instead of a hole through the middle, you get the full width of the pipe back. A repeat clog like this is one of the main signs you actually need hydro jetting. We often run a camera down the line first so you can see the buildup yourself, and again afterward so you can see the clean pipe.

How do I keep my kitchen drain from clogging again?

Keep grease out of the sink. Wipe pans with a paper towel, and pour cooking grease into a can to throw away once it hardens. Run hot water after washing dishes. Skip the chemical drain cleaners, which can damage older pipe without removing the grease. Here is the full list of what not to put down your drain. In older homes with long kitchen lines, a cleaning every year or two keeps things moving.

What about restaurants and commercial kitchens?

Commercial kitchens fight the same problem at a much bigger scale and on a much tighter schedule. See how often a restaurant grease trap needs cleaning, and ask us about jetting your kitchen lines on a regular schedule.

Clean the whole pipe once and the repeat clogs stop

A kitchen sink that keeps clogging is telling you the line is coated, not that you are unlucky. Clearing the full pipe ends the cycle of calling for the same clog every few weeks. Call Snake It Away at (781) 858-8314. A family business since 1997, serving homes and businesses across the Boston metro.

Frequently asked questions

Can I use a chemical drain cleaner on a grease clog?

We would not. Chemical cleaners rarely break down a grease coating along the length of the pipe, and the heat they create can damage older pipe and the trap under the sink. If the sink clears for a day and then slows down again, the cleaner never reached the real problem. The line needs a mechanical cleaning.

Does a garbage disposal cause kitchen sink clogs?

It can add to them. A disposal grinds food smaller, but it does not make grease or starch go away. Coffee grounds, eggshells, potato peels, rice, and pasta still settle in the line farther down and stick to any grease already there. Use the disposal for small scraps only, run plenty of cold water with it, and keep grease out entirely.

Can I snake a kitchen sink myself?

You can clear the trap or the first few feet of line with a hand snake, and for a single clog that may be enough. If the clog is farther down or keeps coming back, a hand snake will not reach the grease along the rest of the line. That is when it is time to call for a professional cleaning.

Does boiling water clear a grease clog?

Not for long. Boiling water can soften grease near the drain and get water moving, but the grease cools and hardens again farther down the pipe. It can also soften plastic pipe joints. Treat it as a short term fix while you schedule a real cleaning.

Why does my kitchen sink smell?

A sour or rotten smell usually comes from grease and food residue sitting in the line and breaking down. Cleaning the trap under the sink may help for a few days, but if the smell comes back, the buildup is farther down the pipe and the whole line needs cleaning.

How often should a kitchen drain line be cleaned?

For most homes, a cleaning every year or two keeps the line clear. Homes that cook a lot, have older cast iron pipe, or have a long run from the kitchen to the main line may need it more often. If the kitchen sink clogs more than once a year, that is a sign the line needs hydro jetting, not another snaking.

Is hydro jetting safe for an older kitchen line?

For pipe in sound condition, yes. We run a camera down the line first to check its condition, then set the pressure to suit the pipe. If a section is cracked or too fragile to jet, we will show you on the screen and recommend another approach.