i30
AEG Dishwasher
Urgency
⚠ High
Stop using immediately
Repair difficulty
🔧 Competent DIY
Some experience required
Diagnosis

What this error means

Anti-flood warning — the dishwasher has detected water in the base tray, indicating an internal leak.

The i30 error on an AEG dishwasher means the anti-flood float switch located in the base tray of the machine has been triggered. AEG dishwashers have a shallow plastic base tray that collects any water escaping from internal leaks. A float switch sits in this tray and activates i30 the moment water is detected. This is a safety-critical protective feature designed to prevent kitchen flooding. The most common causes are excessive foam from too much or the wrong type of detergent, a leaking or perished door seal, a loose or cracked internal hose connection, a leaking pump seal, or a cracked outer tub. The machine will lock out completely until the water in the base tray is physically removed.

⚠️
For information purposes only. Always consult a qualified engineer before attempting repairs. 🔌 Unplug your appliance before any inspection or repair.
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First steps
Fix time
15–30 minutes
🔧
Difficulty
Competent DIY
🏠
Appliance
Dishwasher

What you'll need first

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Step-by-step

1
Unplug the dishwasher from the mains immediately
i30 is a safety-critical fault and the machine must be completely de-powered before any investigation is carried out
2
Do not attempt to start any programme
The anti-flood system is active and the machine will refuse to operate normally until the base tray is confirmed dry
3
Tilt the machine carefully backwards by approximately 45 degrees with a second person assisting
This allows water in the base tray to drain toward the rear ventilation slots and out onto the floor, resetting the float switch
4
Lay towels behind the machine before tilting and allow the base to dry fully before running the machine again or attempting to find the source of the leak
Diagnostic

Symptoms to look for

  1. i30 displayed during or immediately after the start of a programme
  2. Dishwasher completely locks out and will not begin or resume any programme
  3. Water visible on the kitchen floor beneath or in front of the dishwasher
  4. Smell of damp, mildew, or detergent from beneath or around the machine
Step-by-step repair guide

Diagnostic steps

Time 30–60 minutes
Skill Competent DIY
Unplug and prepare safely

Disconnect the dishwasher from the mains power socket immediately. Water in the machine base is in close proximity to the motor, pump, wiring harness, and control board electronics. Investigating or attempting to use the machine while it is powered with water in the base tray is a serious electrocution risk.

Do not attempt to tilt or move the machine with it still plugged in. The combination of water inside the base and mains power is extremely dangerous. Unplug from the wall socket before doing anything else.
Drain the base tray by tilting the machine

With the machine fully unplugged and the water supply tap turned off at the wall, open the under-sink cabinet and pull the dishwasher forward enough to access its sides and rear. With a second person assisting, tilt the machine carefully backwards at approximately 45 degrees and hold this position for 30 to 60 seconds. Water in the base tray will run toward the rear ventilation openings and out onto the floor. Place towels behind the machine before tilting to absorb the water.

Always get assistance before tilting — undercounter dishwashers are heavy and awkward to control alone. Attempting to tilt one single-handed risks dropping the machine, causing personal injury, or damaging surrounding cabinetry.
Allow the base to dry thoroughly

After draining by tilting, stand the machine upright and remove the lower front kickplate panel to allow air to circulate into the base tray area. If possible, direct a hair dryer on a cool, low setting into the base for several minutes to speed drying. The float switch must be completely dry before i30 will clear and normal operation will resume.

Even a few drops of water remaining on or immediately near the float switch will keep i30 active even after the bulk of the water has been drained. Patience and thorough drying are essential — i30 clearing by itself after drying confirms the fault was genuine water ingress and not a switch failure.
Check the detergent type and quantity first

Excessive foam produced by using too much detergent, using non-dishwasher detergent, or using the wrong tablet format overflows during the wash phase and drips into the base tray through internal gaps. This is the single most common cause of i30 in otherwise fully functional machines. Confirm you are using the correct AEG-compatible dishwasher detergent in the correct quantity recommended for your local water hardness setting.

If you recently switched detergent brand or format and i30 appeared shortly afterwards, revert to the previous product. Run an empty 65-degree programme first to flush any foam residue from the tub seal and base before returning to normal use.
Run a leak identification test cycle

Once the base is confirmed dry and i30 has cleared, restore power and water and run a Quick Wash programme. Remain present and observe the machine throughout the full cycle. Watch carefully around the door seal perimeter during the wash phase, beneath the machine at kickplate level during the drain phase, and around the soap dispenser area during filling.

Maintain a safe distance from the front of the machine during this observation test. If water appears quickly from beneath the machine at any point, unplug and turn the water supply off immediately before approaching.
Access and inspect the base tray and float switch

With the machine unplugged and tilted or on its side, remove the base cover panel to view the float switch assembly directly. The float switch arm should be in the lowered, resting position with the base tray completely dry. Confirm the float arm moves freely up and down with no debris or wire obstruction holding it in the raised (triggered) position.

If the base tray is bone dry and i30 continues to appear on every attempt, the float switch itself has failed in the triggered position. Inspect the switch body and its wiring connector — a failed switch or a chafed wire against the float arm will need replacement.
Did this solve your issue?
Escalation

When to call an engineer

  • Door seal is visibly split, perished, torn, or has holes — must be replaced before the machine is used again
  • Pump seal is confirmed leaking — water marks or residue visible around the pump body under the machine
  • Outer tub or base tray has a visible crack or fracture — requires specialist assessment and repair
  • i30 persists with the base tray completely dry — float switch has failed in the triggered position and must be replaced
Common questions

Frequently asked questions

Is i30 dangerous?
Yes — water inside the machine base is in close proximity to live electrical components including the motor, pump, and control board. Never use or investigate the dishwasher while it is plugged in when i30 is active. Unplug first, always, before doing anything.
Can using too much detergent cause i30 on an AEG dishwasher?
Yes — this is the most common cause of i30 in machines that have no physical fault. Excessive foam overflows the tub during the wash phase and drips into the base tray through internal seams. Reduce the detergent dose and use only products designed for automatic dishwashers.
How do I reset i30 after draining and drying the base?
Tilt the machine backwards to drain the tray, allow it to dry thoroughly with the kickplate removed for ventilation, then unplug for 10 minutes and plug back in. The i30 code will clear automatically once the float switch returns to its natural resting position.
Why does i30 keep coming back on my AEG dishwasher?
Recurring i30 always points to a recurring internal leak. Common ongoing causes include a gradually perishing door seal, a worn pump seal, a loose internal hose clamp that vibrates loose during cycles, or consistent over-dosing of detergent. The source of the leak must be identified and permanently fixed.

🎯 What is likely causing this fault?

💧
Internal leak (hoses, seals, sump) 45%
💧
Oversudsing / detergent issue 25%
💧
Residual water from tilt/previous leak 15%
📡
Float switch fault 10%
🔌
Wiring / PCB 5%

⚠️ Estimates based on common faults — not a guaranteed diagnosis. Always verify before ordering parts.

🔩

Parts you may need

Enter your model number to filter results to your exact machine

Usually found on a label inside the door frame or on the back panel of the machine.

No model entered
Part Approx. UK Cost Find it
Door Seal £15 - £30
Door Seal £10 - £20
Float switch £20 - £30

ℹ️ Prices are approximate. Always check the part number matches your model before ordering. Not sure of your model number? Find out how to locate it here.