Direct answer: If your dishwasher leaks when draining, the problem is usually in the drain path, not the fill side. Start with where the water shows up: under the front edge, from the sink air gap, or under the sink near the dishwasher drain hose.
Most likely: The most common causes are a clogged dishwasher filter area forcing water to surge, a blocked sink air gap, or a loose or split dishwasher drain hose connection under the sink.
Drain-time leaks have a pattern. If the machine stays dry during wash and only leaks when it starts pumping out, you can usually narrow it down fast. Reality check: a lot of “dishwasher leaks” turn out to be sink-side drain backups or an air gap spitting water. Common wrong move: running another full cycle with the toe kick off before checking the hose and air gap first.
Don’t start with: Don’t start by ordering a dishwasher drain pump or control part. Most drain-time leaks are caused by blockage, routing, or hose issues you can see.
You hear the drain pump run and water spits or pours from the small fitting on the sink or countertop.
Start here: Start with the air gap cap and the hose from the air gap to the sink drain or disposal. That path is commonly packed with food sludge.
The dishwasher runs normally until drain, then the cabinet floor gets wet near the hose connections.
Start here: Check the dishwasher drain hose, clamps, and the connection at the sink drain or disposal tailpiece while the unit drains.
The floor gets wet in front of the dishwasher, mostly when the pump-out starts or right after.
Start here: Check for a clogged filter or sump area, standing water in the tub, and signs the drain path is restricted and pushing water where it should not go.
You do not see overflow from the door, but water tracks out from the left or right underside during drain.
Start here: Look for a split dishwasher drain hose, a loose internal hose connection, or a drain pump area leak that shows up only under pressure.
When the filter area is packed with debris, the machine can hold extra water and surge during drain. That often shows up as a front-edge leak or messy pump-out.
Quick check: Pull the lower rack, remove the filter if your model has one, and look for standing water, labels, glass, or sludge around the sump.
If water spits from the air gap or backs up under the sink only during drain, the dishwasher is pumping fine but the discharge path is restricted after the machine.
Quick check: Remove the air gap cap and inspect for buildup. Then check the hose from the air gap to the sink drain or disposal for grease and food blockage.
A hose can hold during wash but leak once the drain pump pressurizes it. Kinks, rub-through spots, and sagging loops are common under-sink finds.
Quick check: Dry the hose and fittings, then watch during a short drain cycle. Fresh drips at a clamp or a wet split in the hose usually show up quickly.
If the leak is clearly from underneath the machine and only starts when the pump runs, the pump housing or a nearby internal hose connection may be leaking under pressure.
Quick check: With power off, remove the toe kick and look for mineral tracks or fresh water marks centered near the pump area rather than at the door or under-sink plumbing.
Drain-time leaks look similar from the floor, but the source usually gives the answer. You want to separate sink-side discharge problems from a true dishwasher base leak right away.
Next move: You now know whether the leak is coming from the sink-side drain path or from the dishwasher itself. If you still cannot tell, stop the cycle and dry everything completely before testing again. A dry starting point matters more than a longer test.
What to conclude: Most homeowners save time here. A leak that starts at the air gap or under-sink hose is a different repair than a leak that starts under the dishwasher body.
A restricted drain path is the most common reason a dishwasher leaks only when pumping out. Cleaning is cheap, safe, and often fixes it on the spot.
Next move: If the next drain cycle stays dry, the leak was likely caused by a partial blockage forcing water to back up or surge. If it still leaks, move on to the hose and routing check. At that point you are looking for a pressure leak or a downstream restriction.
What to conclude: When cleaning changes the leak pattern, you are usually dealing with a drain path problem rather than a failed electronic part.
A split hose or loose clamp often leaks only under pump pressure. This is one of the most common under-sink causes and one of the easiest to confirm.
Next move: If tightening or repositioning stops the leak, dry the area and run another full drain to confirm it stays dry. If the hose body is split, brittle, or keeps leaking at a damaged end, replace the dishwasher drain hose. If the hose stays dry, the leak is likely inside the dishwasher base.
Water at the front bottom can come from backed-up tub water spilling forward, or from a leak underneath that just happens to run to the front. Those are different fixes.
Next move: If you see water starting low in the base near the pump or an internal hose, you have narrowed it to an internal pressure leak. If water starts high and runs forward, go back to the drain restriction path. If you still cannot see the source, stop before pulling the dishwasher farther out. Hidden leaks can turn into cabinet and floor damage fast.
Once you know whether the problem is blockage, hose, or pump-area leakage, the next move is usually clear. Guessing past this point wastes time and can flood the kitchen again.
A good result: A full cycle should drain cleanly with no water at the air gap, under the sink, or under the dishwasher.
If not: If it still leaks after a confirmed hose repair and a clean drain path, the remaining likely source is an internal pump or hose connection that needs direct service access.
What to conclude: By this point you should either have a dry machine or a clear reason to stop and get the pump area repaired before more water damage happens.
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That pattern usually means the leak is in the drain path, not the fill system. The most common causes are a clogged filter area, a blocked air gap or sink connection, or a split dishwasher drain hose that leaks only when the pump pressurizes it.
Yes. If the sink-side connection or air gap is restricted, the dishwasher can pump water faster than that path can carry it away. The water may spit from the air gap or leak under the sink even though the dishwasher itself is fine.
Not usually. A door gasket problem tends to leak during wash when spray is hitting the door area. If the machine stays dry until pump-out starts, look at the drain path and hose first.
No. A drain pump is not the first bet on this symptom, and it is a discouraged guess-buy. Confirm the simple stuff first: filter area, air gap, sink connection, and drain hose. Only chase the pump if the leak clearly starts at the pump area during drain.
That usually points to a stronger drain restriction or a separate not-draining problem. Clean the filter and sink-side discharge path first. If standing water remains, move to a dishwasher not draining diagnosis instead of treating it as a leak-only issue.
It is better not to. Small drain-time leaks often become bigger once the hose shifts or the blockage worsens, and repeated wetting can damage cabinets and flooring before the leak looks serious.