How to Clear Grease From a Drain | The Steps That Work

Grease buildup is the most common reason a kitchen sink drains slowly or stops entirely. The fix for how to clear grease from a drain starts with the hottest tap water your plumbing can handle, plus ordinary dish soap — no harsh chemicals required. Here is the step order that actually works, along with the limits you need to know before you pour anything down the sink.

Start With Hot Water and Dish Soap

A fresh grease clog often dissolves with nothing more than heat and degreaser. Dish soap breaks up fat, and hot water carries it through the pipes. This method is the first move because it is safe, cheap, and works on most blockages.

• Run the hottest tap water your faucet produces, or heat water on the stove and let it cool to about 160–180°F.
• Add 2–3 tablespoons of dish soap directly into the drain.
• Wait 5 minutes so the soap can work on the grease.
• Flush with more hot water for a full 2 minutes.

If the water still drains slowly after one pass, repeat the cycle once. Two attempts are the limit — if the drain has not cleared by then, the blockage is likely farther down the line or hardened into a plug that hot water cannot soften.

When to Plunge or Use a Drain Snake

If hot water and dish soap do not free the line, mechanical force is the next tool. A plunger or a drain snake/auger physically breaks through the grease instead of dissolving it, and both work where chemicals fail.

Plunging technique: use a standard cup plunger, position it over the drain opening to create a tight seal, and pump 10–15 times with firm strokes. Finish by running hot water and dish soap again to wash the freed grease through.

Snaking the line: if plunging stalls, insert a drain snake into the pipe, rotate it clockwise to bite into the grease, and push until you break through the blockage. Retract the snake while continuing to rotate, then flush with hot water. Before snaking, remove standing water from the sink so you can see what you are doing.

One more culprit sits right under the sink. The P-trap — the curved pipe below the basin — collects grease before it ever reaches the wall. Place a bucket beneath it, loosen the slip nuts, and pull the curved section free. Clear out the grease plug by hand, reassemble the trap, and check for leaks by running water for a minute.

What Not to Pour Down the Drain

Skip the baking soda and vinegar. Despite its popularity, this fizzing combination is ineffective against grease clogs. One plumbing source notes the reaction mostly produces water and carbon dioxide — nothing with real degreasing power. You will get better results from hot water alone.

Never use a chemical drain cleaner for grease. Caustic products can damage pipes, especially older metal lines, and they are hazardous to handle. A plumber’s advice is blunt: keep chemical cleaners away from grease clogs entirely.

Watch the temperature with PVC pipes. Plastic plumbing can soften around 140°F, so boiling water is a genuine risk for PVC. If you are unsure what your pipes are made of, stick with tap water at its hottest setting.

Also, never keep adding water to a sink that is not draining. The basin fills quickly, and overflow defeats the whole effort.

When It Is Time to Call a Plumber

Two failed attempts at hot water and dish soap, plus a plunging session, point to a deeper problem. The clog is either far down the main line or it has hardened into a solid plug that household tools cannot break apart. Continuing to work on it risks overflow and wasted effort, and a professional auger or hydro-jetting service will clear it faster than anything you can rent.

Before calling, check the P-trap yourself — it is a five-minute job that accounts for a surprising share of “stubborn” grease clogs. If the trap is clean and the drain still refuses to move water, the blockage is past your reach. A plumber can also identify whether your pipes have larger issues, like bellied sections where grease collects repeatedly.

For the long term, prevent the problem instead of fighting it. Wipe greasy pans with a paper towel before washing, scrape cooking fat into a jar, and run hot water for 30 seconds after each dishwashing session. These three habits stop grease from building up in the first place. If you prefer a preventive product, our tested roundup of the best drain cleaners for grease covers formulas that work without damaging pipes.