What does water standing in the bottom of a dishwasher mean?
Water standing in the bottom of a dishwasher means the last drain did not finish, unless it is only a little clean water in the sump. A small amount under the filter is normal and keeps the pump seals wet.
- Dirty water over the filter after the cycle: the filter, hose, sink trap or drain pump is blocked.
- Dirty water that appears later: waste is flowing back from the sink through the drain hose.
- Pump hums and no water moves: the pump impeller is jammed.
Common causes of a dishwasher not draining
The common causes run from an interrupted programme to a failed drain pump, simplest first.
At a glance
| Cause | Typical sign | Who fixes it |
|---|---|---|
| Interrupted programme | Water left after a power cut | You can check this |
| Blocked filter or sump | Water sits over a dirty filter | You can check this |
| Kinked hose or no high loop | No flow, or sink water runs back | You can check this |
| Blocked sink trap or spigot plug | Sink drains slowly, or new installation | You can check this |
| Drain pump | Pump hums or is silent | Technician |
| Non-return valve | Dirty water returns after draining | Technician |
- 1
The programme was interrupted
You can check thisA dishwasher drains only at set points in the programme. Load shedding, a tripped plug point or a door opened mid-cycle leaves water inside. Close the door, reset the programme and let it drain.
- 2
The filter or sump is blocked
You can check thisThe filter in the tub floor stops food scraps reaching the drain pump. Grease, pips, glass chips and labels block the filter and the sump beneath it, and water sits over them. Twist the filter out and wash it. A blocked filter also causes a dishwasher not cleaning properly.
- 3
The drain hose is kinked or has no high loop
You can check thisThe drain hose runs from the pump to the sink waste. A kink behind the machine blocks the flow. The hose must also rise to the underside of the worktop, or sink water runs back into the dishwasher.
- 4
The sink trap is blocked or the spigot plug was left in
You can check thisThe hose connects to a spigot on the sink trap. Grease blocks the spigot over time. On a new installation, the blanking plug inside the spigot is sometimes left in, so the first programme cannot drain.
- 5
The drain pump impeller is jammed or the pump has failed
TechnicianThe drain pump pushes waste water up the hose. A jammed impeller makes the pump hum with no flow. A failed pump is silent during the drain. A technician clears or replaces it.
- 6
The non-return valve is stuck
TechnicianThe non-return valve is a rubber flap at the pump outlet that stops drained water flowing back. When debris holds it open, dirty water returns to the sump after each drain. A technician cleans or replaces it.
What you can safely check yourself
- Switch off and unplugSwitch off at the plug point and unplug. Let hot water cool.
- Clean the filter and sumpScoop out the water, twist out the filter and wash it. Wear gloves, because broken glass collects in the sump.
- Check the drain hoseLook under the sink for a kink and confirm the hose rises in a high loop.
- Check the sink trapRun the sink tap. If the sink drains slowly, clear the trap and the hose spigot.
- Run a short programmeRefit the filter, run a rinse programme and listen for the pump.
When to stop and call a technician
Stop and unplug the dishwasher if you smell burning, the machine trips the earth leakage or water is on the floor near the plug point. Stop if the pump hums or stays silent with a clean filter. Stop if the fault returns after one reset. Do not remove the base, panels, wiring or control board.
Still having trouble with your dishwasher?
Our technician comes to your home, usually the same day. The R450 call-out falls away if you go ahead, and you get a fixed price in writing before any work starts.
How a technician diagnoses a dishwasher that is not draining water
- Runs the drain testThe technician starts the drain pump in service test mode and reads any error code.
- Clears the drain pathThe sump, non-return valve, pump housing and drain hose are stripped and cleared.
- Tests the drain pumpThe pump winding is measured and the impeller is checked.
- Checks the base and controlThe base tray is checked for leaked water, and the control board output to the pump is measured.
How do you fix a Bosch dishwasher not draining?
To fix a Bosch dishwasher not draining, start with the filter, sump, drain hose and sink trap. Bosch and Siemens machines show a drain fault as E24 or E25. On many Bosch models, the pump cover in the sump lifts out so you can clear the impeller. Unplug the machine first and follow the manual. A code that returns needs a dishwasher repair technician.
Is a dishwasher that is not draining worth repairing?
Repair usually makes sense when
- The fault is a blocked filter, sump, hose or sink trap
- The drain pump or non-return valve has failed
- The tub, racks and door seal are in good condition
Replacement is worth considering when
- The control board has failed on an old machine
- The tub or base is rusted or leaking
- The circulation pump or heater has also failed