How to Unclog a Kitchen Sink
If you have used any chemical drain cleaner, do NOT plunge or disassemble the P-trap until the chemical has been fully flushed. Chemical drain cleaners cause severe burns on contact with skin.
What You'll Need
- 1/2 cup
- 1/2 cup
- Full kettle
- 1
- 1 if needed
- 1
- 1 pair
Step-by-Step Method
Boil a full kettle. Pour the boiling water directly down the drain in 2-3 stages, waiting a few seconds between each pour. This melts grease clogs. If the water drains, the clog is cleared.
If boiling water did not work: pour 1/2 cup baking soda down the drain, followed by 1/2 cup white vinegar. Cover the drain opening with a wet cloth to force the fizzing action downward. Wait 15-30 minutes, then flush with boiling water.
Fill the sink with 3-4 inches of water. Place a cup plunger over the drain and pump vigorously 15-20 times. If you have a double sink, plug the other drain with a wet cloth so the pressure focuses on the clog.
Place a bucket under the P-trap (the curved pipe under the sink). Unscrew the slip nuts by hand or with pliers. Remove the P-trap and clean out any debris. Reassemble.
If the clog is beyond the P-trap, insert a 25-foot drain snake into the wall pipe. Feed it in while turning the handle clockwise. When you hit resistance, work the snake back and forth to break through.
- Do not use chemical drain cleaners (they corrode pipes over time and are hazardous)
- Do not pour grease down the drain (the #1 cause of kitchen sink clogs)
- Do not use a plunger if you have already poured chemical drain cleaner (it can splash back)
- Prevention: run hot water for 30 seconds after each use, especially after washing greasy dishes
- Monthly maintenance: pour 1/2 cup baking soda + 1/2 cup vinegar down the drain once a month to prevent buildup
- Install a mesh drain strainer to catch food debris before it enters the drain
Frequently Asked Questions
The three most common causes: grease buildup (solidifies in pipes), food debris bypassing the garbage disposal, and soap scum combining with grease to form hard blockages. Monthly baking soda + vinegar maintenance prevents most recurring clogs.
No. They contain sodium hydroxide (lye) or sulfuric acid, which corrode metal and PVC pipes over time, damage septic systems, and create hazardous fumes. They also often do not fully clear the clog, just open a small channel that clogs again quickly. Mechanical methods (plunger, snake, P-trap cleaning) are always better.
Sources & Methodology
Plumbing methods based on standard residential practices. Chemical drain cleaner warnings based on EPA hazardous materials guidelines.
Last reviewed: March 20, 2026