How to Unclog a Kitchen Sink

A kitchen sink usually clogs from a slow buildup of grease, food scraps, and soap scum coating the trap and horizontal drain line. Here's how to tackle it safely.

Common causes

• Grease and cooking oil poured down the drain
• Coffee grounds, rice, or pasta expanding in the trap
• Soap scum lining the pipe walls
• Failing or misaligned P-trap

Step-by-step

1. 01Boil a kettle and pour hot (not boiling on PVC) water down the drain in two stages
2. 02Try a cup plunger with the second basin sealed and water covering the cup
3. 03Remove and clean the P-trap into a bucket — most clogs sit right here
4. 04If the trap is clear, run a hand auger 3–5 feet into the branch line

When to call Northbridge

• Water backs up in both basins or into the dishwasher
• Clog returns within days of clearing
• You hear gurgling in other fixtures when the sink drains
• You smell sewage under the sink