Quick answer
A kitchen sink that will not drain is usually a grease and food clog in the trap or the pipe just past it. Run the garbage disposal first, since a jammed disposal blocks the sink. On a double sink, seal the other drain and plunge with a cup plunger, then try hot water with dish soap, then remove and empty the trap. If the trap is clear and the sink still holds water, the clog is in the wall and a plumber clears it with a snake; drain cleaning runs $100–$275 (HomeServe). Call (888) 217-6781 to reach a plumbing company taking calls in your ZIP.
Follow the short menu, then your 5-digit ZIP. The line goes quiet for a few seconds while it connects; stay on. If it does not connect, call once more: companies taking calls change minute to minute.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed October 27, 2026· Next review Apr 2027
A kitchen sink that drains slowly or holds standing water is almost always grease and food set into a solid plug in the trap or the pipe just past it. A double sink that backs up into the other bowl, or a sink that backs up when the dishwasher runs, is the same clog with a different symptom.
Try These First, in Order
- 1Check the garbage disposal. If the sink has one, run it with cold water. A disposal that hums without spinning is jammed, and a jammed disposal blocks the sink above it; see garbage disposal not working.
- 2Plunge with the other side sealed. On a double sink, plug the other drain with a stopper or a wet rag, fill the clogged side with a few inches of water and plunge with a cup plunger. Without the seal, the pressure just comes up the other side.
- 3Hot water, not boiling, and dish soap. A kettle of hot water (hot from the tap or a kettle that has cooled off the boil) with a squeeze of dish soap can loosen a grease plug. Boiling water can soften PVC joints and crack porcelain.
- 4Clear the trap. Put a bucket under the U-shaped trap, loosen the two slip nuts by hand and empty it. If the trap is clear and the sink still will not drain, the clog is in the wall or beyond.
Skip chemical drain cleaners if you plan to plunge or open the trap: the caustic water splashes back.
What Each Sign Points To
| What you see | Likely cause | Who fixes it |
|---|---|---|
| One side backs up into the other | Clog below the point where the two bowls join | You (plunger, trap), then a plumber |
| Trap is clear, still standing water | Grease clog in the branch line inside the wall | Plumber with a drain snake |
| Sink backs up when the dishwasher drains | Shared drain clogged | Plumber |
| Sink and nearby tub or toilet are slow too | Main sewer line | Plumber; see main sewer line clog |
| Slow drain that comes back every few weeks | Grease building up along the pipe | Plumber; ask about cleaning the line, not just punching through |
Talk to a plumber about this
One call reaches a plumbing company taking calls in your ZIP.
What a Repair Costs
HomeServe's range for drain cleaning is $100–$275, and plumber labor runs $70–$120 an hour plus a trip fee and parts according to Angi. A main-line clog costs more. The drain cleaning page has the sources.
When to Call
Call once the trap is clear and the sink still will not drain, or if the clog comes back. (888) 217-6781 connects you to a plumbing company taking calls in your ZIP. Follow the short menu, enter your 5-digit ZIP and stay on while it connects; if it does not connect, call once more, because the companies taking calls change minute to minute.
Reading to confirm what you already suspect?
Confirm it in two minutes instead — the pro on this line answers questions about YOUR situation all day: what it is, what it should cost, whether you even need service. If you want, they'll set the appointment on the same call.
No obligation to book
Frequently Asked Questions
Why is my kitchen sink not draining?
Grease and food scraps harden into a plug in the trap or the drain line in the wall. A jammed garbage disposal or a clog shared with the dishwasher drain can cause the same thing.
Why does my double kitchen sink back up into the other side?
The clog is below the point where the two drains join, so water from one bowl can only go up the other.
How much does a plumber charge to unclog a kitchen sink?
HomeServe's range for drain cleaning is $100–$275. Angi puts plumber labor at $70–$120 an hour plus a trip fee and parts.
Should I use chemical drain cleaner on a kitchen sink?
Not if you plan to plunge or open the trap afterwards: the caustic water can splash back. It also does little against a hardened grease clog in the wall.
Sources
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
Equipment
What each machine actually does
Removes the moisture the structure is still giving off — the machine that decides how long drying takes
See the picks →Moves air across wet surfaces so the dehumidifier has something to take out of the air
See the picks →Finds water behind walls and under floors, and tells you when a material is actually dry
See the picks →Alerts you the moment a leak starts; a small cost, and the one preventive item here
See the picks →Those pages carry affiliate links. As an Amazon Associate, HearthDry earns from qualifying purchases; it costs you nothing extra.
Our Amazon storefront →