Kitchen Sink Not Draining? One Side, Both Sides & Disposal Clogs
When only one basin backs up, the clog sits in that basin's trap or its short arm. When both sides fill, the blockage is past the tee where they join, deeper in the branch or main line. That single distinction tells you whether this is a fifteen-minute P-trap job or a call to a plumber.
Describe the symptom to a pro
A local licensed plumber can usually tell you over the phone whether it needs a visit.
(855) 000-0000New installs, replacements & repairs · No obligation
Safety first: if you smell gas, see water near electrical outlets or your panel, or sewage is contacting living areas, get people clear first. For a gas smell, leave and call 911 or your gas utility's emergency line before anything on this page.
- !Both basins are full and water rises in a floor drain or another fixture when you run the sink: the clog is in the main line
- !Dark, greasy water or waste backs up into the sink: the blockage is deep and possibly shared with the sewer line
- !Water gurgles up through the basin when the dishwasher drains or the washing machine empties
- !A sewage smell rises with the standing water
- !The backup returns within hours of clearing, suggesting the line is nearly full downstream
- ✓Confirm one side vs both: a single clogged basin points to that trap; both basins point past the shared tee into the branch line
- ✓On the disposal side, run the disposal with water for ten seconds: a humming or jammed unit can mimic a drain clog (clear the jam before assuming a clog)
- ✓Bail out standing water, place a bucket under the P-trap, and unscrew the two slip nuts by hand to remove and clean the trap: the most common clog lives right here
- ✓Check the disposal discharge tube and the trap arm into the wall for grease and food packed solid
- ✓Plunge the clogged basin with the other basin's drain sealed (a stopper or wet rag) and the dishwasher hose clamped, so pressure goes toward the clog
- →Both basins stay clogged after you clean the P-trap: the blockage is past the tee in the branch line
- →You can reach the clog with a hand snake but cannot break through it
- →The sink re-clogs within days, a sign of grease coating the branch line walls
- →Gurgling or backup that involves the dishwasher, disposal and sink together
- →Any backup that also shows up in a floor drain or another room
Not sure what you are looking at? Just ask.
Calls are answered around the clock and routed to a licensed plumbing pro serving your area.
Call & describe the job
Tell us what you need: a new install, a replacement, or something that started leaking.
Get matched on the line
You are connected with a local licensed plumbing pro who serves your area.
Compare your numbers
Use the ranges on this page to sanity-check the quote before you commit.
One side or both sides: read the clue first
A double-bowl kitchen sink has two drains that join at a tee, then share one trap and one arm into the wall. If only one basin holds water while the other drains fine, the clog is in that basin's side before the tee: usually its own trap or the disposal discharge. That is the easier fix.
If both basins fill up, water cannot get past the point where they join, so the clog is at or beyond the tee, in the shared trap arm or the branch line behind the wall. Both-sides-clogged is the signal that the blockage is deeper than a quick trap cleaning, and it is why these often end in a plumber's snake rather than a plunger.
The disposal side has its own logic
If the clogged basin holds the garbage disposal, rule the disposal out before you touch the drain. A unit that hums without spinning is jammed, and a jammed disposal blocks the drain just like a clog would. Cut the power, turn the flywheel loose with the hex wrench in the bottom slot, clear the jam, then test it with running water. Our guide to a disposal that will not work walks the reset and jam-clearing steps.
If the disposal spins freely but the basin still backs up, the clog is downstream of it, in the discharge tube, the trap, or the branch line. Never reach into a disposal, and never run it against standing water hoping to clear a drain: it cannot pump through a blocked pipe and you risk burning out the motor.
The P-trap walkthrough (the most common fix)
The P-trap is the U-shaped pipe under the sink, and it catches more clogs than anywhere else in the kitchen. Removing and cleaning it is the single most useful homeowner skill here. Bail the standing water first so the basin is empty, then set a bucket and old towel underneath because the trap is full of water.
Loosen the two slip nuts, the plastic rings at each end of the U, by hand or with channel-lock pliers turned gently. Slide the trap off and you will usually find it packed with grease, coffee grounds or food. Clean it out, check the trap arm going into the wall for more buildup, then reassemble hand-tight and run water to check for leaks.
- ·Bucket and towel first: the trap holds standing water that will pour out
- ·Hand-tighten the slip nuts on reassembly, then snug a quarter-turn if it weeps
- ·If the trap is clean but the basin still backs up, the clog is past it in the wall
Grease is the real enemy
Most kitchen clogs are grease, not solids. Liquid fat washes down warm, then cools and congeals on the pipe walls, narrowing the branch line over months and catching every coffee ground and food scrap that follows. That is why a kitchen drain can clog with no single dramatic event: the line simply closed up.
Because grease coats the whole pipe, clearing it is different from clearing a hair mat. A snake punches a hole through the plug but leaves the greasy walls behind, so the clog often returns. For a line that keeps closing, scouring matters more than poking, which is where jetting earns its place.
What each fix costs
The DIY path costs almost nothing: cleaning the P-trap takes only a bucket and ten minutes, and a flat plunger runs $10 to $20. That clears most single-basin clogs.
When the blockage is past the trap, a plumber typically charges $150 – $400 to snake the kitchen branch line, depending on access and where the clog sits. For grease-fouled lines that re-clog, hydro jetting the pipe scours the walls back to bare pipe and runs more than a basic snake but lasts far longer. If the kitchen backup is one of several around the house, whole-line drain cleaning and a camera look settle whether the main line is involved.
Keep the line open
The simplest fix is the grease you never pour. Wipe greasy pans with a paper towel before washing, pour bacon fat into a can for the trash, and keep coffee grounds, eggshells and fibrous peels out of the disposal. These three habits prevent most kitchen clogs outright.
Run cold water while the disposal works and for fifteen seconds after, which firms up food so it chops rather than smears. Once a week, run hot water for a full minute to flush light grease before it sets. A sink you maintain rarely needs a snake.
Ready to get it handled?
One call, no obligation. Describe the job and compare the quote against the ranges above.