A kitchen sink that won’t drain is almost always grease and food buildup narrowing the pipe. Here’s what helps, what to skip, and when to call.
Written bySteven Lockhart·Reviewed byMiguel Lopez, Owner & Licensed Plumber, New Pro Plumbing (CSLB #974600)·Last reviewedAugust 2026 · 7 min readQuick Answer
A clogged kitchen sink is usually caused by grease, food scraps, and soap building up on the pipe walls until water can’t pass. Try a plunger and hot water first; avoid chemical drain cleaners, which often don’t clear grease and can damage pipes. If both basins back up or it keeps recurring, the clog is deeper in the line. New Pro clears kitchen drains fast across West LA.
A kitchen sink that drains slowly or not at all is almost always the result of grease and food building up inside the pipe. Grease goes down warm and liquid, then cools and hardens on the pipe wall, catching food scraps, coffee grounds, and soap scum until the opening narrows to nothing. It builds gradually, which is why the drain gets slower and slower before it finally stops.
Clogged kitchen sink — Clogged kitchen sink repair is the clearing of a blocked kitchen drain — usually grease, food, and soap buildup — by cabling or hydro jetting the line, not chemical cleaners.
A plunger and hot water clear a minor one, but a hardened grease clog deeper in the line is a job for an emergency plumber with the right tools.
Chemical drain cleaners often don’t clear grease and can damage pipes and harm anyone working on standing water later.
If the tub or shower is slow too, the clog may be past the branch, toward the main line — a slow shower drain at the same time is a clue.
Try the safe basics, then bring in the tools.
Bail out standing water so you can work.
A sink plunger over the drain often shifts a soft clog.
Very hot water can help soften and flush light grease.
They rarely clear grease and can damage pipes.
Both backing up means it’s past the shared drain.
We cable or hydro jet the line clear.
Keeps clogging? Recurring grease clogs need more than a snake — hydro jetting scours the pipe wall clean so it stops coming back.
Sink full of standing water? We’ll clear the line — call us.
Get a Free QuoteGrease is deceptively destructive because of how it behaves. It goes down the drain warm and liquid, seeming harmless, then cools just a few feet into the pipe and solidifies on the wall. Each time it happens, the coating thickens and grabs whatever comes past — food particles, coffee grounds, soap — until the pipe’s opening shrinks to a trickle. By the time the sink stops draining, there’s often a hardened plug that a plunger simply can’t move.
This is also why chemical drain cleaners so often disappoint on kitchen clogs: they’re formulated more for hair and organic matter than for a wall of congealed grease, and pouring them onto a grease plug frequently just leaves you with a clogged drain full of caustic chemicals. The U.S. EPA points to grease and improper disposal as leading causes of drain and sewer blockages, which is why prevention — keeping grease out of the drain entirely — beats any product you can pour in after the fact.
For a line already caked in grease, the lasting fix is to physically clean the pipe, and that’s what a cable or, better, a hydro jetting does. We clear it as licensed work you can verify with the CSLB (#974600), and for the rare kitchen clog that turns out to be a branch or main-line defect, we permit any repair through the Los Angeles Department of Building & Safety. Mostly, though, it’s a straightforward clear and a reminder to trash the grease.
How often it clogs decides whether a snake or a jet is right.
| Situation | Method | Result |
|---|---|---|
| One-off soft clog | Plunge / cable | Cleared |
| Recurring grease | Hydro jetting | Scours pipe clean |
| Whole-kitchen slow | Cable the branch | Restores flow |
We clear it and tell you if it’ll come back — flat-rate, the way 24/7 emergency plumbing should be.
A simple kitchen clog is an affordable clear; cost rises only if the buildup is heavy and needs hydro jetting rather than a cable, or if the clog is deep in the line. We diagnose how far and how bad it is, then quote flat-rate — no hourly clock.
See how our emergency plumbing service prices drain clearing flat-rate.
A homeowner's kitchen sink backs up in both basins during holiday cooking, with standing greasy water.
New Pro cables the branch drain, clears a hardened grease plug, and recommends jetting to prevent a repeat.
Both basins drain freely again, and the homeowner knows to keep grease out of the drain going forward.
The Bottom Line
A clogged kitchen sink is almost always grease doing what grease does. A plunger and hot water handle the minor ones; a hardened or recurring clog needs a cable or a jet. The one thing to skip is chemical drain cleaner — it rarely beats grease and can make the pipe, and the plumber’s job, worse.
The overwhelming cause is grease and food buildup. Cooking grease poured or rinsed down the drain cools and hardens on the pipe walls, and over time it traps food scraps, coffee grounds, starches, and soap scum until the pipe narrows and clogs. It’s a gradual process, which is why the sink usually drains slower and slower before it stops entirely. Fibrous foods, coffee grounds, and starchy items like pasta or rice are especially prone to contributing.
It’s best avoided. Chemical drain cleaners are often ineffective on the grease clogs that cause most kitchen sink backups, and they can corrode pipes — especially older ones — with repeated use. They also create a hazard: if the cleaner doesn’t clear the clog, a plumber later faces standing water full of caustic chemicals. A plunger, hot water, or a professional clearing with a cable or jet is safer and more effective.
When both basins of a double sink back up, the clog is past the point where the two drains join — in the shared branch drain rather than one basin’s trap. That means it’s deeper in the line and usually beyond what a plunger will reach. It often indicates a more substantial grease or food blockage that needs a drain cable or hydro jetting to clear properly, rather than a quick fix at the sink.
The key is keeping grease out of the drain: let cooking grease cool and throw it in the trash rather than pouring it down, and wipe greasy pans before washing. Use a drain strainer to catch food scraps, avoid putting coffee grounds and fibrous or starchy foods down, and run hot water after washing greasy dishes. For a drain with heavy existing buildup, a hydro jetting scours the pipe clean so you start fresh.
A cable snake bores through a clog and restores flow, which is fine for a one-off blockage. Hydro jetting uses high-pressure water to scour grease and buildup off the entire pipe wall, restoring the full diameter and flushing it away. For a kitchen line with recurring grease clogs, jetting lasts far longer because it removes the buildup causing the problem rather than just punching a hole through it. We recommend based on how often it’s clogging.
Written by the New Pro Plumbing content team and reviewed for technical accuracy by Miguel Lopez, owner and California-licensed plumber (CSLB #974600). Guidance follows U.S. EPA, CSLB, and LADBS sources where cited. Any figures reflect New Pro Plumbing's flat-rate practice and West LA conditions, not a quote — we confirm pricing in writing before any work begins.
Last reviewed: August 2026.
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