Step-by-Step DIY Fix Guide
- SAFETY: Disconnect power at the breaker.
- Check that the water supply valve under the sink is fully open.
- Inspect the inlet hose for kinks or damage.
- Turn off the water supply, disconnect the inlet hose from the valve, and check the screen filter inside the valve inlet for sediment. Clean if clogged.
- Restore connections, turn water back on, restore power, and run a test cycle.
If it's still not filling correctly
- If normal household water flow looks good but the code returns, the inlet-valve or fill-sensing path becomes more likely.
- If airflow still seems weak after the basic checks, the fan path or a deeper obstruction becomes more likely.
- If the warning returns immediately after a clean restart, the sensor or wiring path becomes more likely than a one-time glitch.
What This Error Means
Error code E18 on your Bosch dishwasher indicates: There is an issue with water flow into the dishwasher. The water level is too low, or water is not being pumped correctly. The appliance detects this condition through its built-in sensors and halts the current cycle to prevent further damage. Depending on the model, the code may flash on the display panel, appear on a digital readout, or cause the status lights to blink in a specific sequence. The dishwasher will not resume normal operation until the underlying fault is resolved.
The most frequent cause of error E18 is water supply pressure too low (below 7 psi). When this happens, the dishwasher's control board detects the abnormal sensor reading or motor response and triggers the fault code as a protective measure. Other contributing factors are listed in the causes section below — working through them in order is the fastest path to a fix.
Many cases of error E18 can be resolved with DIY troubleshooting — start with the steps below before calling a technician. If the steps do not clear the code, the fault is deeper in the system and professional diagnosis will be needed. The guide specifies clearly at which point to stop DIY work.
The most visible symptom of E18 is water where it shouldn't be — either too much inside the tub, or water detected in the base tray beneath the dishwasher. Turn off the water supply valve under the sink before investigating, and lay towels around the base of the unit while troubleshooting.
What users usually notice before this code
Bosch dishwasher warnings like this often show up after standing water, slow draining, heavy food residue, or a cycle that never returned to normal at the end.
Common misdiagnoses
- Assuming the display code proves one exact failed part before the safe first checks are done.
- Blaming a pump or valve first when a blocked path, filter, hose, or household plumbing issue is still possible.
- Replacing a lock or latch too early when alignment, trapped laundry, or startup conditions may still explain the warning.
Most Likely Cause by Symptom
The Bosch dishwasher may stop, pause, or refuse to complete the cycle normally.
Likely cause: Water supply pressure too low (below 7 psi)
Check first: SAFETY: Disconnect power at the breaker.
The warning may return immediately because the appliance is detecting an internal fault.
Likely cause: Partially closed supply valve under the sink
Check first: Check that the water supply valve under the sink is fully open.
Common Causes
- Water supply pressure too low (below 7 psi)
- Partially closed supply valve under the sink
- Kinked or blocked water inlet hose
- Clogged water inlet valve screen filter
What Not to Do
- Do not run further cycles until the fault is resolved
Model and Display Variation Notes
Model-family notes
- Bosch dishwasher display wording and code formats can vary by series.
- If your model behaves differently, check the owner manual before trying any deeper maintenance step.
Display and panel differences
- Panel wording can vary by series, so confirm the exact code pattern before buying parts.
Parts, Tools and Service Options
Common parts
- Water inlet valve ($25–$60)
- Inlet hose ($15–$30)
Manual and model check
Check your exact model and manual before ordering any Bosch dishwasher parts.
Service option
Bosch service visit if the warning returns after the basic checks are complete.
Suggestions in this section are organized to support the troubleshooting flow first. Any future affiliate relationships should be disclosed clearly.
When Not to Keep Troubleshooting
Household water pressure is confirmed below 7 psi — call a plumber
- Inlet hose and screen are clear but E18 persists
How to Prevent It Recurring
- Check water pressure at the dishwasher annually — it should be between 7 and 87 psi
Related Error Codes
E14
Bosch dishwasher error E14 usually means the machine is having trouble measuring incoming water correctly during fill.
E16
Bosch dishwasher error E16 usually means there is a problem with the water fill system, often because the inlet valve is not controlling water flow properly.
E3200
There is an issue with water flow into the dishwasher. The water level is too low, or water is not being pumped correctly.
Helpful guides for this problem
Guide
What to check before replacing a dishwasher drain pump
The checks worth doing before you blame the drain pump and spend money on a fix that may not be the real problem.
Guide
How to tell if a dishwasher problem is drainage or leak-protection related
How to tell whether a dishwasher water-related warning is about drainage or a more cautious leak-protection stop.
Guide
Most common Bosch dishwasher error codes and what they usually mean
A clearer look at the Bosch dishwasher codes owners run into most often and what is worth checking before booking service.
When not to keep pushing DIY troubleshooting
Use the code page for one careful first pass, then stop if the same warning returns or the appliance still cannot get back to normal operation.
Extra notes
- This page is based on Bosch support material and stays conservative where model-specific guidance may vary.
- The goal is to help you identify safe first checks before you move into parts, service, or model-specific manual lookup.
Source and model notes
Last reviewed: 2026-04-07
Based on: Based on Bosch support material and edited into consumer-safe guidance for the exact code family on this page.
Model coverage note: Bosch dishwasher code meanings can vary by series, control panel, and model family, so use this page as a safe starting point rather than a replacement for the model-specific manual.
Important: FixThisError is an independent guide, not the manufacturer. Use your model-specific manual when the panel wording or behavior differs.
Always disconnect power before inspecting appliances. If unsure, contact a licensed appliance technician.