The E18 error on your Bosch Dishwasher means the machine's Aquastop water protection system has detected a leak or excess water in the base tray. Turn off the water supply and check under the unit before running another cycle.
| Error code | E18 |
|---|---|
| Meaning | Aquastop leak detection triggered or water inlet/flow fault |
| Severity | High — the dishwasher will stop working until the leak is cleared |
| Time to fix | 15–45 minutes |
| Tools needed | Towels, torch, adjustable pliers |
What the E18 error means
Bosch dishwashers use a float switch and safety valve system called Aquastop to protect your kitchen from flooding. When water collects in the base pan, or when the machine senses a problem with water flow in or out, it triggers the E18 code and locks the dishwasher out of its cycle. This is a safety feature, not a random glitch, so it's worth taking seriously rather than restarting the machine repeatedly.
The fault can stem from a genuine leak, a stuck float switch, or a blocked drain hose causing water to back up. In some cases it's a false alarm caused by condensation or a splash from a previous cycle.
Common causes
- Water leaking from the tub seal, spray arm, or door gasket
- A loose or damaged hose connection at the water inlet or drain
- The float switch in the base tray stuck in the "up" position
- A blocked or kinked drain hose causing water to overflow
- Excess detergent or foam causing overflow during the wash cycle
- A faulty Aquastop valve on the inlet hose
How to fix the E18 error
- Turn off the water supply and power: Shut off the stop valve feeding the dishwasher and unplug the unit before inspecting anything.
- Check the base tray for water: Tilt the dishwasher forward slightly and look underneath for pooled water. Mop up any moisture with towels.
- Inspect the float switch: Open the front kick panel and check that the float sits freely and isn't jammed by debris or a dropped item.
- Examine hoses and connections: Look at the inlet and drain hoses for cracks, loose clamps, or kinks that could cause backflow or leaks.
- Clear drain blockages: Remove and rinse the drain filter and check the drain hose for clogs, similar to how you'd clear debris from any household appliance.
- Reset and test: Reconnect the water and power, then run a short rinse cycle without dishes to confirm the error has cleared.
If you're comfortable doing your own appliance troubleshooting, it helps to have the right approach for other Bosch tools too — for example, knowing why a Bosch Drill Won'T Start often comes down to a similar mix of power and connection issues. The same careful, step-by-step checking applies whether you're dealing with a dishwasher or diagnosing a Bosch Drill Overheating During Use.
FAQ
Can I just reset the dishwasher and ignore the E18 code?
A. You can try a reset, but if there's an actual leak the code will return quickly. It's safer to check the base tray and hoses first.
Is E18 dangerous to my kitchen floor?
A. Yes, if left unchecked a persistent leak can damage flooring and cabinets, so it's worth addressing promptly rather than repeatedly restarting the cycle.
Do I need a technician to fix E18?
A. Not always. Many cases are caused by a stuck float switch or loose hose, which you can check yourself. If the Aquastop valve itself is faulty, professional replacement is usually needed.
