Dishwasher Not Draining: What Is Wrong and What to Check
If water sits in the bottom of the tub after a full cycle, the drain path is blocked somewhere between the filter and the sink drain. In the homes we visit across Los Angeles and Orange County it is almost always one of six things: a clogged filter, a blocked air gap, a kinked or clogged drain hose, a knockout plug left in a new garbage disposal, a jammed drain pump, or a stuck check valve. The first two you can clear yourself in about fifteen minutes. The rest need the machine pulled out.
What causes it
| Cause | What you see | Who fixes it |
|---|---|---|
| Clogged filter and sump | Standing water with food debris, a smell after a day | You can clear it |
| Blocked air gap on the sink | Water bubbles up at the small chrome cap next to the faucet | You can clear it |
| Knockout plug in a new garbage disposal | The dishwasher has never drained since the disposal was replaced | You, or the installer who fitted it |
| Kinked or clogged drain hose | Slow drain, the machine hums, the water level barely moves | Technician |
| Jammed or failed drain pump | A hum with no water movement, or no sound at all | Technician |
| Stuck check valve | The tub drains, then fills back up with dirty water | Technician |
Bosch dishwashers not draining
Bosch machines block at the same six points, with two differences worth knowing. The filter is a fine three part cylinder that clogs slowly and silently, and in hard water areas like ours it wants a rinse every few weeks rather than every few months. And where most machines simply sit full of water, a Bosch with a display usually says what it found: E24 means the drain path is blocked, most often the filter or a kinked hose, and E25 means the drain pump itself is blocked, usually by a shard of glass or a fruit label wrapped around the impeller. Neither code is a failed part on its own, both clear once the blockage is out. On most models that impeller sits directly under the filter behind a small cover, so it can be reached without pulling the machine out from under the counter.
Five stops on the way out. The blockage is sitting at one of them.
What you can check yourself
- Switch the dishwasher off at the breaker before you reach inside.
- Scoop out the standing water with a cup, then soak up the rest with a towel.
- Twist out the filter in the bottom of the tub, rinse it under the tap, and clear the sump underneath it by hand.
- Pull the cap off the air gap next to the faucet and clear whatever is inside.
- If a garbage disposal was installed recently, check that the installer knocked out the dishwasher plug. This one catches people out constantly.
- Run a rinse cycle and listen. A hum with no drainage means the pump is jammed. Silence means the pump is dead or the control is not calling for it.
Where to stop
Stop if water still stands after the filter and the air gap are clean, if the pump hums without moving water, or if the machine trips the breaker. Everything past that point means pulling the unit out from under the counter and opening the pump housing, and a slip there turns a drain repair into a leak under the cabinet.
Call C&C Appliance Repair at (800) 860-0974 for same-day service across Los Angeles and Orange County.
Air gap, hose loop and disposal inlet: the three places to look.
What the visit looks like when the blockage is past the filter.
Questions we get asked
Is standing water in the dishwasher dangerous?
Not immediately, but it turns stale within a day and it runs onto the floor the next time the door is opened wide. Bail it out before you leave it.
The garbage disposal is new and the dishwasher has not drained since. Why?
A new disposal ships with a solid plug in the dishwasher inlet. If the installer does not knock it out, the dishwasher has nowhere to drain. It is a five minute fix and it is the most common cause we see right after a kitchen job.
Can I just run the cycle again to clear the blockage?
Running it again on a blocked drain does nothing useful, and it can burn out the pump if the impeller is jammed. Clear the filter first, then try one cycle.
How long does the repair take?
Most drain repairs are done in a single visit. Our vans carry drain pumps and hoses for the common brands, so there is usually no second trip for parts.
Which brands do you work on?
All of them, including Bosch, Miele, KitchenAid, Thermador, Viking, Sub-Zero, LG and Samsung. Bosch and Miele in particular use a fine filter that clogs quietly, with no warning at all, until the machine stops draining.
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