Why does my kitchen sink drain slowly even after I clean it?

Which part of the sink is slow?

Warm grease may look as though it washed away, but it can cool and stick farther along the pipe. Seattle Public Utilities notes that hot water and soap do not prevent this and that a disposal only makes food pieces smaller. ^[1]

Once the pipe wall is coated, food particles and other material have a surface to collect on. Cleaning the strainer or polishing the disposal opening does not reach that branch buildup.

What you can check without opening the drain

• Confirm whether one or both bowls are affected.
• Listen for a disposal that hums, stalls, or drains only while running; follow its manufacturer instructions and keep hands out.
• Look for leakage at visible slip joints beneath the sink without loosening them over a full basin.
• Note whether the dishwasher, another sink, or laundry discharge changes the water level.

Keep more grease out of the drain

1. Let cooking fats cool and scrape or wipe them into the trash or another locally accepted waste stream.
2. Use a sink strainer and empty food scraps before washing dishes.
3. Do not rely on hot water, detergent, or the disposal to carry grease through the pipe. ^[1]
4. Report any drain chemical used, even if it did not improve flow.

A disposal makes food smaller, but its outlet, rubber baffle, and connected trap can still clog. If the motor hums or the turntable is jammed, follow the appliance manual. Never place a hand inside the grinding chamber, even when the wall switch is off.

Opening the trap beneath a full sink can release the entire basin and any drain product into the cabinet. If standing water remains or the fittings are corroded, let the plumber empty the basin safely and open the joint in a controlled way. The material found beyond the trap helps determine the cleaning method.