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Kitchen sink drain · Repair Copilot

Kitchen sink backing up

A kitchen sink backing up usually has a grease-and-food clog in the trap or the branch drain just past it — the spot where cooled fats and coffee grounds collect. Most of it clears with a plunger or by opening the P-trap. Show SightLine the sink and under-cabinet plumbing and a plumber persona walks you through clearing it without harsh chemicals.

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Steps to fix kitchen sink backing up

  1. If there's a garbage disposal, run it with cold water first to rule out a jam; if it only hums, that's a separate disposal fix.
  2. For a double sink, plug the OTHER basin, add a few inches of water, and plunge the clogged side firmly — the plug forces pressure down the drain instead of sideways.
  3. Skip chemical drain cleaners — they rarely cut grease and make snaking or opening the trap hazardous.
  4. Clear the cabinet, put a bucket under the P-trap, unscrew the slip nuts by hand, and clean the grease and food out of the trap and the arm going into the wall.
  5. If the trap is clear but it still backs up, run a small hand auger into the wall stub-out to reach a clog farther down the branch line.
  6. If multiple fixtures back up together, or water rises in another drain when this one runs, stop — that's a main-line problem for a plumber, not a sink clog.

Safety first: if a step calls for gas, a main water or sewer line, a service panel or main breaker, or a sealed refrigerant system, stop and call a licensed pro — Repair Copilot will tell you when you're there.