The E21 error on your Siemens Dishwasher means the appliance is unable to drain water properly. This code indicates a drainage system fault that prevents the dishwasher from emptying water at the end of a cycle.
| Error code | E21 |
|---|---|
| Meaning | Drainage system fault - water not pumping out |
| Severity | Medium — dishwasher will not operate until resolved |
| Time to fix | 15–45 minutes |
| Tools needed | Towels, bucket, pliers, screwdriver (possibly) |
What the E21 error means
The E21 error code signals that your Siemens dishwasher has detected a problem with draining water. This typically occurs when the drain pump cannot remove water from the tub within the expected time frame. The dishwasher's control system monitors the drainage process and triggers this error when water remains in the base or tub after the pump has run. The error prevents the dishwasher from starting a new cycle to protect against water damage and flooding.
Common causes
- Blocked or kinked drain hose preventing water from flowing out
- Clogged filter or debris trapped in the pump chamber
- Blocked sink or waste pipe that the dishwasher drains into
- Faulty drain pump that cannot expel water effectively
- Food particles or broken glass obstructing the drainage system
- Incorrect drain hose installation or height exceeding manufacturer specifications
How to fix the E21 error
- Switch off and bail out standing water Turn off the dishwasher at the power supply. Open the door carefully and use towels and a container to remove any standing water from the bottom of the tub. This makes the next steps safer and easier.
- Clean the filters thoroughly Remove the bottom spray arm if necessary, then lift out the filter assembly located in the dishwasher floor. Rinse the coarse filter and fine mesh filter under running water, removing all food debris, grease and foreign objects. Refit the filters securely.
- Check and clear the drain pump area Remove the filter assembly completely to access the pump chamber beneath. Check for debris, broken glass, bones, fruit stones or other objects blocking the impeller. Remove any obstructions carefully and ensure the impeller can spin freely.
- Inspect the drain hose Pull the dishwasher forward to access the drain hose at the back. Check for kinks, twists or blockages along its length. Disconnect the hose from the waste connection and check both the hose and the sink spigot for blockages. Ensure the hose is not installed higher than 100cm from the floor.
- Test the drain pump Run a short rinse cycle to see if water drains properly. Listen for the drain pump running. If the pump makes unusual noises, runs but does not pump water, or does not run at all, the pump may be faulty and require replacement.
- Check the household waste pipes If the dishwasher still will not drain, check your sink waste for blockages. A blocked sink or standpipe will prevent the dishwasher from draining. Clear any blockages in the household plumbing before restarting the dishwasher.
FAQ
Can I reset the E21 error on my Siemens dishwasher?
You can attempt a reset by switching off the dishwasher at the mains for 5 minutes, then switching it back on. However, the E21 error will return if the underlying drainage problem is not resolved. You must fix the cause of the blockage or fault for the error to clear permanently.
Is it safe to use my Siemens dishwasher with an E21 error showing?
No, you should not use the dishwasher while the E21 error is displayed. The appliance has detected a drainage fault and will not complete a wash cycle. Attempting to run it may cause water to overflow from the base or leak onto your floor, potentially causing water damage to your kitchen.
How much does it cost to fix an E21 error on a Siemens dishwasher?
If you can clear the blockage yourself by cleaning filters and checking hoses, the repair costs nothing. If you need to replace the drain pump, expect to pay between 40 and 80 pounds for the part, plus 80 to 150 pounds for labour if you hire an engineer. Many E21 errors can be resolved without professional help.
