Standing water after the cycle ends
There is a visible pool of water in the tub floor, often with food bits floating in it.
Start here: Start at the filter and sump area, then move to the drain hose and sink-side connection.
Dishwasher Drain Problem
LG Dishwasher Not Draining
Direct answer: If your LG dishwasher is not draining, the usual cause is a blockage in the filter area, sump, drain hose, air gap, or sink drain connection. A failed dishwasher drain pump is possible, but it is not the first thing I would blame.
Most likely: Start with standing water in the tub, then check the dishwasher filter, the sump opening under it, the drain hose for kinks, and the sink-side drain connection or air gap for grease and debris.
When a dishwasher finishes and leaves dirty water in the bottom, you want to separate a simple drain path blockage from a real pump failure fast. Reality check: a little clean water in the very bottom can be normal, but a puddle covering the sump or floating debris is not. Common wrong move: running cycle after cycle with standing water just packs food sludge deeper into the drain path.
Don’t start with: Do not start by ordering a dishwasher drain pump. Most no-drain calls turn out to be a clog or a bad hose routing issue.
If you hear the drain motor run but water barely moves,look for a clog in the filter, sump, hose, air gap, or sink connection before replacing parts.
If it is silent during the drain portion,check for a jammed impeller area, wiring issue, or a failed dishwasher drain pump after the easy blockage checks.
Last reviewed: 2026-04-17
What the drain failure looks like
Humming or buzzing during drain
You hear the machine trying to drain, but the water level barely drops.
Start here: Look for a blocked impeller area, clogged hose, or plugged air gap before assuming the motor is bad.
No drain sound at all
The cycle ends with water still inside and you do not hear the usual pump-out sound.
Start here: Check for a jam in the sump first, then consider a failed dishwasher drain pump or an electrical issue.
Water drains out, then comes back
The tub empties partly, then dirty water reappears later.
Start here: Focus on the sink drain branch, air gap if present, and drain hose routing to rule out backflow.
Most likely causes
1. Clogged dishwasher filter or sump opening
This is the most common cause when water sits in the bottom and the machine still otherwise runs. Food scraps, labels, glass chips, and grease collect right where the drain path starts.
Quick check: Remove the lower rack, pull the dishwasher filter, and look for sludge or debris packed around the sump opening.
2. Kinked or restricted dishwasher drain hose
A hose can flatten behind the machine, clog with grease, or sag in a way that slows the drain badly.
Quick check: Look under the sink and behind the dishwasher for a sharp bend, crushed section, or heavy buildup where the hose connects.
3. Blocked sink air gap or sink-side drain connection
If the dishwasher drains into an air gap or a branch tailpiece at the sink, that connection can plug up and make the dishwasher look like the problem.
Quick check: Remove the air gap cap if you have one and check for gunk, or disconnect the dishwasher hose at the sink-side fitting and inspect the inlet.
4. Failed or jammed dishwasher drain pump
If the drain path is clear and the unit is silent or only hums during drain, the pump may be seized, damaged, or not moving water.
Quick check: After clearing the easy clogs, listen during a drain command. A dead-silent or harsh humming pump with no water movement points this way.
Step-by-step fix
Step 1: Confirm it is really a drain problem, not just normal residual water
A shallow film or a little clean water below the filter area can be normal. You want to avoid tearing into a machine that is actually draining as designed.
- Open the dishwasher right after the cycle ends, not hours later after sink use.
- Look at the tub floor and note whether water is just below the filter area or pooled above it.
- If the water is dirty, greasy, or has food floating in it, treat it as a real drain problem.
- Cancel or drain the cycle once and listen for the drain portion so you know whether the machine is trying to pump out.
Next move: If the water clears and only a small clean amount remains low in the sump area, the dishwasher may be draining normally. If water stays pooled in the bottom or comes back after draining, keep going.
What to conclude: You are separating normal residual water from a true no-drain or backflow problem.
Stop if:
- Water is spilling onto the floor.
- You smell burning insulation or see smoke.
- The dishwasher trips the breaker when it tries to drain.
Step 2: Clean the dishwasher filter and clear the sump area
This is the highest-payoff first check. Most dishwasher no-drain complaints start right here.
- Shut off power to the dishwasher before putting your hands into the sump area.
- Remove the lower rack and take out the dishwasher filter assembly.
- Wash the dishwasher filter with warm water and mild dish soap. Use a soft brush only if needed.
- Wipe sludge and food debris out of the filter well and sump opening.
- Carefully check for broken glass, labels, bones, or hard debris around the impeller area without forcing anything.
Next move: If the dishwasher drains normally after reassembly, the blockage was at the filter or sump. If the water still will not leave, the restriction is likely farther down the drain path or the pump is not moving water.
What to conclude: A dirty dishwasher filter can choke off flow enough to leave standing water, but a clean filter with the same symptom pushes you toward the hose, sink connection, or pump.
Step 3: Check the drain hose path and the sink-side connection
Once the filter area is clear, the next most common trouble spot is the hose or the place where it empties into the sink plumbing.
- Look under the sink for the dishwasher drain hose and trace it from the dishwasher to the sink drain or air gap.
- Straighten any sharp kinks and make sure the hose is not crushed behind stored items or cabinet framing.
- If there is an air gap on the sink deck, remove the cap and clean out debris inside it.
- Disconnect the dishwasher drain hose from the sink-side fitting or disposal inlet and inspect for grease or food blockage.
- If the hose is clear, check the sink-side inlet itself for a plug of sludge and clean it out before reconnecting.
Next move: If water now pumps out strongly, the restriction was in the hose, air gap, or sink connection. If the hose and sink connection are clear and the dishwasher still will not drain, move on to pump behavior.
Step 4: Listen to the drain pump and watch how the water behaves
Sound and water movement tell you a lot. A working pump with a blockage sounds different from a failed pump.
- Restore power and run a cancel-drain or short cycle that reaches drain.
- Listen closely near the lower front of the dishwasher.
- If you hear a steady motor sound and the water level drops slowly or not at all, suspect a remaining restriction or a weak pump.
- If you hear a loud hum, grinding, or intermittent buzz with little movement, the dishwasher drain pump may be jammed or damaged.
- If you hear nothing during the drain portion and the rest of the machine has power, the dishwasher drain pump or its electrical feed is a stronger suspect.
Next move: If the pump sounds normal and water exits strongly after your cleaning, you likely cleared the problem. If the pump is silent, harsh, or moving almost no water with a clear drain path, plan on pump-level repair.
Step 5: Replace the failed drain-path part or call for service if the diagnosis is still muddy
By now you should know whether you had a clog, a damaged hose, or a likely pump failure. The right next move is clearer and cheaper than guessing.
- Replace the dishwasher drain hose if it is split, permanently kinked, or packed with buildup you cannot clear fully.
- Replace the dishwasher filter if it is broken, will not lock in place, or is missing sections that let debris pass into the sump.
- Replace the dishwasher drain pump if the drain path is clear and the pump is silent, seized, or only hums without moving water.
- If the dishwasher still will not drain after those checks and you have no clear pump evidence, schedule service for electrical diagnosis rather than buying more parts.
A good result: If the dishwasher finishes a full cycle and the tub is left with only normal residual water, the repair is done.
If not: If standing water returns even after a clear drain path and a confirmed part replacement, the problem is beyond a simple homeowner repair.
What to conclude: You have moved from cleanup into confirmed repair. Replace only the part your checks actually support.
Replacement Parts
Repair Riot may earn a commission from qualifying purchases, at no extra cost to you.
FAQ
Why is my LG dishwasher leaving water in the bottom?
Most of the time it is a clogged dishwasher filter, debris in the sump, a restricted drain hose, or a blocked sink-side connection. A bad dishwasher drain pump is possible, but it is usually not the first cause.
Is a little water in the dishwasher normal?
Yes. A small amount of clean water low in the sump area can be normal. A visible puddle across the tub floor, dirty water, or floating food debris is not normal.
Can a clogged sink drain keep the dishwasher from draining?
Yes. If the dishwasher drains into a sink tailpiece, disposal inlet, or air gap, a blockage there can stop the dishwasher from emptying or can let dirty water run back into the tub.
How do I know if the dishwasher drain pump is bad?
After the filter, hose, and sink connection are confirmed clear, a bad pump usually shows up as silence during drain, a loud hum with no water movement, or grinding from the pump area.
Should I use drain cleaner in a dishwasher that will not drain?
No. Chemical drain cleaners can damage dishwasher parts, seals, and hoses, and they create a safety hazard when you open the drain path later. Clean the filter, sump, hose, and sink connection mechanically instead.
Why does the dishwasher drain and then fill back up later?
That usually points to backflow from the sink side. Check the air gap if you have one, the sink drain branch where the dishwasher hose connects, and the hose routing under the sink.