How to Clean a Kitchen Sink Grease Trap

Grease is the silent enemy of your kitchen plumbing. Over time, animal fats and oils cool as they pass through the drain, hardening into a stubborn, waxy layer that eventually chokes the P-trap beneath your sink. When you notice sluggish drainage or a faint, sour smell emanating from the drain, it is time to intervene before a total blockage forces a call to a professional. Performing this maintenance yourself saves on plumber fees and keeps your pipes flowing freely. Done well, this job is surgical—clean, efficient, and odor-free. By setting up a proper catch basin and working methodically, you can clear the obstruction without coating your entire cabinet in kitchen sludge.

1. Clear Your Work Zone. Remove everything from under the sink to give yourself room to maneuver. Place an old towel or a plastic tray on the floor of the cabinet to catch any accidental drips.
2. Catch Every Drop. Place a bucket or a deep plastic container directly underneath the P-trap pipe. This ensures that when you loosen the slip nuts, the standing water and sludge fall into the bucket rather than on the cabinet floor.
3. Free the Trap Gently. Use your channel-lock pliers to gently turn the two large plastic nuts holding the P-trap in place. If they are tight, wrap a rag around them to prevent scratching the finish before applying torque.
4. Release and Drain. Carefully slide the P-trap downward to release it from the tailpiece and the drain line. Pour the trapped water into your bucket and inspect the interior for the grease plug.
5. Blast Away the Buildup. Use a stiff brush or a disposable scraper to dislodge the solidified grease from inside the pipe walls. Rinse the pipe thoroughly in a separate basin—not the kitchen sink—using hot water and degreasing dish soap.
6. Seal and Verify. Slide the trap back into place, ensuring the rubber washers are seated properly. Tighten the slip nuts by hand until firm, then run hot water for two minutes to check for leaks.