Why Won't My Siemens Washing Machine Drain?
Clean out the pump filter located behind the small access panel at the bottom front of the machine — a blocked filter is the cause in the majority of cases and clearing it should restore normal draining within about 10 minutes.
Fault description
When a Siemens washing machine won't drain, you'll typically find standing water left in the drum at the end of a cycle, or the machine pauses mid-programme and refuses to continue. The display may show error codes E20, E21, E23, or E24 — all of which relate to a drainage fault detected by the machine's control system. E23 and E24 specifically point toward a pump or wiring issue, while E20 and E21 indicate the machine simply couldn't empty within the expected time.
The drainage system on a Siemens washing machine involves several components working together: the pump filter, the drain pump motor, the drain hose, and the pressure sensor that tells the machine when the drum is empty. A problem with any one of these can bring the whole process to a halt. The good news is that the most common causes are straightforward to check and fix yourself without specialist tools.
Causes
- Blocked pump filter — The pump filter traps lint, coins, hair grips, and other small items before they reach the pump impeller. Over time it becomes clogged and restricts water flow enough to prevent draining entirely.
- Kinked or blocked drain hose — The corrugated drain hose can become kinked behind the machine or blocked with a build-up of detergent residue and debris. Even a partial blockage creates enough back-pressure to stop the pump from emptying the drum.
- Faulty or jammed drain pump — If a foreign object — such as a small coin or piece of wire — gets past the filter and into the pump, it can jam the impeller. The pump motor may also fail electrically, which is what error codes E23 and E24 typically indicate.
- Blocked household standpipe or sink trap — The fault isn't always inside the machine. If the standpipe or the sink trap the drain hose empties into is partially blocked, water cannot exit quickly enough and the machine registers a drain error.
- Faulty pressure sensor or air chamber — The pressure sensor (also called a pressure switch) monitors the water level in the drum. If the small rubber air chamber tube connected to it is blocked with detergent residue, the sensor may incorrectly report that the drum is still full even after draining.
- Wiring or control board fault — In less common cases, the wiring harness between the control board and the drain pump can develop a break or poor connection, preventing the pump from receiving power. Error codes E23 and E24 can point to this when the pump and filter are both clear.
Step-by-Step Fix
- 1
Manually drain the drum first
Before doing anything else, you need to remove the standing water. Place towels on the floor, then open the small access panel at the bottom front of the machine. Slowly unscrew the cap on the pump filter — there is a small emergency drain hose next to it on most Siemens models. Direct this hose into a shallow bowl and let the water drain out in stages. This prevents a flood when you remove the filter.
- 2
Clean the pump filter
Once the water is out, fully unscrew and remove the pump filter. Rinse it under a tap, removing all lint, debris, and any foreign objects. Check inside the filter housing with a torch for anything lodged in the pump impeller — you should be able to turn the impeller freely with your finger. Refit the filter firmly and run a short spin cycle to test.
- 3
Check the drain hose for kinks or blockages
Pull the machine gently away from the wall and inspect the entire length of the drain hose. Straighten any kinks and ensure the hose is not pushed too far down into the standpipe — it should sit no deeper than 15 cm into the pipe to allow air circulation. Disconnect the hose and flush water through it to confirm it is clear.
- 4
Check the household standpipe or sink trap
Pour a bucket of water directly into the standpipe or sink that the drain hose connects to. If it drains slowly, the blockage is in your household plumbing rather than the machine. Clear the trap or standpipe using a standard drain cleaner or plunger before testing the washing machine again.
- 5
Inspect and test the drain pump
If the filter was clear and the hose is unobstructed, the pump itself may be faulty. With the machine unplugged, access the pump from the front or rear depending on your model. Check that the pump wiring connector is firmly seated. Reconnect power and start a drain or spin cycle — a working pump makes a consistent low hum. No sound at all suggests an electrical fault; a grinding noise suggests a jammed impeller.
- 6
Check the pressure sensor air chamber tube
Locate the thin rubber tube running from the bottom of the drum up to the pressure sensor on the side of the cabinet. Disconnect it at both ends and blow through it to confirm it is clear. Rinse it with warm water if you feel any resistance. A blocked tube can cause the machine to behave as though the drum is full even when it has drained.
- 7
Reset the machine and run a test cycle
After completing any of the above checks, reset the machine by switching it off at the wall for two minutes, then switching it back on. Select a short spin-only programme to confirm draining is working correctly. If an error code reappears immediately without the drum containing water, a component fault is likely and a service technician should be consulted.
When to call a service technician
If you have cleaned the filter, cleared the hose, and confirmed the household plumbing is free-flowing but the machine still won't drain, the drain pump motor has most likely failed and needs replacing. Similarly, if error codes E23 or E24 return immediately after a reset with no obvious blockage present, there is likely a wiring or control board fault that requires diagnostic equipment to trace safely.
You should also call a service technician if you notice any burning smell coming from the machine during a drain attempt, if the pump housing shows signs of cracking or water leakage around it, or if the machine trips your household circuit breaker when it tries to drain — these are signs of an electrical fault that should not be investigated without professional training.
Prevention
The single most effective thing you can do to prevent drain faults on a Siemens washing machine is to clean the pump filter every one to three months, depending on how frequently you use the machine. Empty pockets before loading — coins, hair grips, and tissues are the most common causes of pump blockages and impeller damage. Running a hot maintenance wash (60°C or above) with a washing machine cleaner once a month also helps prevent detergent residue from building up in the drain hose and pressure sensor tube.
The parts most commonly replaced when a Siemens washing machine develops a persistent drain fault are the drain pump assembly, the pump filter housing (if cracked during cleaning), and the pressure sensor. Genuine Siemens-compatible versions of all three are available as spare parts.
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Frequently Asked Questions
What do error codes E20, E21, E23, and E24 mean on a Siemens washing machine?
All four codes relate to a drainage problem. E20 and E21 mean the machine tried to drain but couldn't empty within the allowed time — usually pointing to a blockage. E23 and E24 indicate the control board has detected a fault with the drain pump circuit itself, such as a failed pump motor or a wiring issue. Start by checking the filter regardless of which code appears.
Can I use my washing machine if it won't drain?
It is not advisable. Running further cycles with standing water in the drum can put extra strain on the pump motor and may cause mould and odour to develop quickly. Resolve the drain fault first, then resume normal use.
How do I get the water out of my Siemens washing machine if it won't drain?
Use the small emergency drain hose located next to the pump filter at the bottom front of the machine. Place a shallow tray underneath, pull out the hose, remove its cap, and let the water flow out gradually. You may need to empty the tray several times for a full drum load.
How often should I clean the pump filter on my Siemens washing machine?
Every one to three months is a good general guideline. If you wash items that shed a lot of lint — such as towels or pet bedding — or if you frequently wash items with small items in the pockets, clean it monthly. Regular cleaning takes less than five minutes and prevents the majority of drain faults.
Is a drain pump replacement something I can do myself?
Many confident DIYers do replace drain pumps on Siemens washing machines, as the pump is generally accessible from the front after removing the filter housing. However, it does involve disconnecting electrical connectors and hose clips, and the machine must be unplugged throughout. If you are not comfortable working around appliance wiring, it is safer to have a service technician carry out the replacement.