Pump runs with little water in the tub
You hear the drain pump or a steady hum, but the tub is already mostly empty.
Start here: Check the dishwasher float first, then look for water in the base pan under the tub.
Dishwasher troubleshooting
Dishwasher Keeps Draining
Direct answer: When a dishwasher keeps draining, the usual cause is not a bad board right away. More often the machine thinks water is still where it should not be, so it keeps the drain pump running. Start by checking for water in the tub or base, a stuck dishwasher float, and a clogged filter or drain path.
Most likely: The most likely causes are a stuck dishwasher float, debris in the dishwasher filter and sump area, a restricted dishwasher drain hose or sink air gap, or water collected in the base pan tripping the leak protection.
First pin down which kind of draining you have: water visibly leaving the tub, a humming or pumping sound with little water movement, or a dishwasher that starts draining again as soon as you close the door. That split matters. Reality check: a lot of "keeps draining" calls turn out to be a clog or a float issue, not an expensive electrical failure. Common wrong move: canceling cycles over and over without cleaning the filter and checking the air gap or drain hose first.
Don’t start with: Do not start by ordering a control board or drain pump just because you hear the pump running.
If there is standing water in the tub,check the filter, sump opening, air gap, and dishwasher drain hose before suspecting parts.
If the tub is mostly empty but the pump keeps running,look for a stuck dishwasher float or water in the base pan triggering leak protection.
Last reviewed: 2026-04-06
What this usually looks like
Standing water stays in the bottom
The dishwasher keeps draining but water still sits in the sump or tub floor.
Start here: Start with the dishwasher filter, sump debris, sink air gap, and dishwasher drain hose restriction.
Dishwasher begins draining right away at startup
You start a cycle and it goes straight into drain mode instead of filling and washing.
Start here: Look for a stuck float or leak protection triggered by water in the base.
Drain sound is loud or strained
The pump sounds rough, rattly, or louder than normal while trying to drain.
Start here: Check for broken glass, labels, or food debris around the dishwasher drain pump inlet before assuming the pump itself is bad.
Most likely causes
1. Dishwasher float stuck up or float switch held in the full position
If the dishwasher thinks the water level is too high, many models will keep draining or refuse to move on to fill.
Quick check: Find the float inside the tub floor area and make sure it moves up and down freely without grit, soap buildup, or a utensil trapping it.
2. Clogged dishwasher filter, sump opening, or drain path
A partial blockage can leave water behind, so the machine keeps trying to pump out what it never fully clears.
Quick check: Remove the lower rack, inspect the dishwasher filter and sump area, and check the sink air gap and dishwasher drain hose for grease or food sludge.
3. Water in the dishwasher base pan triggering leak protection
On many dishwashers, even a small leak into the base will trip a float or sensor and the drain pump may run continuously.
Quick check: Look for water on the floor, damp insulation, or sloshing sounds when the dishwasher is gently moved. If safe to access, inspect the base area for moisture.
4. Dishwasher drain pump jammed or failing
If the pump is noisy, overheated, or only hums while little water moves, the impeller may be jammed or worn.
Quick check: After power is off, inspect the pump inlet area for glass, bone fragments, twist ties, or labels that can lock up the impeller.
Step-by-step fix
Step 1: Figure out whether it is actually moving water or just running the pump
You need to separate a real drainage problem from a false full-water signal. The next checks are different.
- Cancel the cycle and let the dishwasher finish its drain attempt.
- Open the door and note whether there is standing water above the filter area, just a shallow puddle near the sump, or almost no water at all.
- Listen to the sound: a normal drain is a steady pump sound with water moving into the sink drain or air gap. A strained hum, rattling, or dry-sounding pump points a different direction.
- If your sink has an air gap on the counter, watch it during drain. If water spits out there, the downstream drain path is restricted.
Next move: If the dishwasher drains normally and then stays quiet, the issue may have been a one-time clog or interrupted cycle. Run a short rinse cycle and watch it. If it keeps trying to drain, move to the float and blockage checks next.
What to conclude: Standing water points toward a clogged filter or drain path. An empty tub with nonstop pumping points more toward a stuck float or water in the base pan.
Stop if:
- You smell burning plastic or hot electrical odor.
- Water is spilling onto the floor.
- The drain sound is harsh enough that it seems the pump is running dry for more than a brief moment.
Step 2: Check the dishwasher float and clear the easy debris points
A stuck float is one of the fastest, safest fixes, and filter debris is the most common reason water never fully leaves.
- Shut off power to the dishwasher at the breaker or unplug it if accessible.
- Remove the lower rack.
- Locate the dishwasher float on the tub floor if your model has a visible one. Lift it gently and let it drop. It should move freely and settle back down without sticking.
- Make sure no utensil, bottle cap, label, or hardened detergent is wedged around the float.
- Remove and clean the dishwasher filter with warm water and mild dish soap. Wipe sludge and debris from the sump opening area you can safely reach.
- Reinstall the filter correctly and make sure it locks in place.
Next move: If the float was stuck or the filter was packed with debris, the dishwasher may stop draining nonstop and return to a normal fill-and-wash cycle. If the float moves freely and the filter area is clean, check the drain path outside the tub.
What to conclude: A float that sticks up can keep the machine in drain mode. A dirty filter or sump can leave enough water behind to trigger repeated drain attempts.
Step 3: Check the sink-side drain path and dishwasher drain hose
A dishwasher can keep draining simply because the water has nowhere to go. This is especially common after sink work or disposal replacement.
- Inspect the sink air gap if you have one. Remove the cap and clear food sludge with warm water and a small brush or cloth.
- Look under the sink at the dishwasher drain hose. Make sure it is not kinked, crushed, or sagging badly.
- If the dishwasher drains through a garbage disposal, confirm the disposal is clear and was properly opened if recently installed.
- Disconnect the dishwasher drain hose from the sink-side connection only if you can do it without making a mess, then check for grease plugs or food buildup near the end of the hose.
- Reattach the hose securely and keep a proper high loop if your setup uses one.
Next move: If the hose or air gap was blocked, the dishwasher should drain once and move on instead of repeatedly pumping. If the drain path is clear and the machine still keeps draining, the next likely issue is leak protection or a pump problem.
Step 4: Look for water in the base pan and signs of leak protection
Many dishwashers will run the drain pump continuously when water collects in the base, even if the tub itself looks empty.
- Turn power off again before inspecting lower access areas.
- Look for water on the floor in front of the dishwasher, damp toe-kick insulation, or mineral tracks under the door.
- If you can safely remove the lower access panel, inspect for standing water in the base pan or obvious wet spots around hoses, the pump area, or the inlet side.
- If you find a small amount of water in the base, dry it thoroughly and then run a short cycle while watching for the source of the leak.
- Pay close attention to drips from the door area, hose connections, and the pump housing.
Next move: If drying the base stops the nonstop draining, you have confirmed leak protection was the reason. The real fix is finding and correcting the leak source. If the base is dry and the dishwasher still keeps draining, the drain pump or level-sensing hardware becomes more likely.
Step 5: Decide between a jammed drain pump, a bad float assembly, or a pro call
By this point you have ruled out the common easy causes. Now you want one clean next move instead of guessing.
- If the pump is loud, rattly, or only hums and you found debris near the pump inlet, clear what you safely can and test again.
- If the pump still runs rough with a clear drain path and no base water, the dishwasher drain pump is a reasonable suspect.
- If the dishwasher goes straight to drain with a dry base, clear filter area, and a float that does not move or feels damaged, the dishwasher float or float switch assembly is a reasonable suspect.
- If symptoms are inconsistent, or if the machine keeps draining even after those checks with no clear mechanical clue, stop before buying electronics and schedule service for live testing.
A good result: If clearing the jam or replacing the confirmed failed mechanical part solves it, run a full cycle and recheck for leaks and normal fill timing.
If not: If a confirmed mechanical fix does not change the symptom, professional diagnosis is the smart move because the remaining causes usually require electrical testing and model-specific access.
What to conclude: A noisy or jammed pump supports a drain pump repair. A stuck or damaged float supports a float repair. No clear mechanical clue means do not guess at expensive controls.
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FAQ
Why does my dishwasher start draining as soon as I turn it on?
That usually means the dishwasher thinks there is an overfill or leak condition. The common causes are a stuck dishwasher float, water in the base pan, or leftover water from a blocked drain path that never fully cleared.
Can a clogged sink drain make a dishwasher keep draining?
Yes. A restriction at the sink connection, garbage disposal inlet, or air gap can keep the dishwasher from emptying properly. The pump keeps trying because the water is not leaving the system the way it should.
Is it normal for a dishwasher to drain first at the start of a cycle?
A brief initial drain can be normal on many models. What is not normal is a drain pump that keeps running for long stretches, restarts repeatedly, or never moves on to fill and wash.
Should I replace the dishwasher drain pump if I hear it running?
Not first. If the pump runs, that only tells you the machine is trying to drain. Check the float, filter, air gap, hose, and base pan before blaming the pump. Replace the pump only when the drain path is clear and the pump is jammed, noisy, or not moving water properly.
What if the dishwasher tub is empty but the pump still runs?
That points away from a simple tub clog and more toward a stuck float or leak protection triggered by water in the base. It can also happen with a control or sensing problem, but those are not the first things to assume.
Can I keep using the dishwasher if it eventually stops on its own?
It is better not to. Repeated drain-only behavior can overwork the pump, hide a small leak, or leave dirty water where it should not be. Fix the cause before regular use.