Bosch E22: Aqua-Sensor Detects Dirty Water

Low severity

E22 means Bosch's aqua-sensor has picked up cloudy, dirty water sitting in the sump beneath the filter, which is nearly always the result of a clogged filter.

Cycles end with an odd smell, a film left on glasses, or food bits still stuck to plates, and E22 shows up on the display right alongside it. It's usually the friendliest code Bosch makes — fixing it is mostly a five-minute cleaning job rather than a repair.

Applies to: Bosch dishwashers with electronic displays (most 300/500/800 series models).

What it means

The dishwasher's aqua-sensor has detected dirty, cloudy standing water in the sump beneath the filter, almost always because the filter itself is clogged and blocking normal water flow.

The aqua-sensor is an optical sensor that checks how clear the wash water is between fill and drain; once it can no longer 'see through' the water, it assumes the filter isn't doing its job and throws the code rather than keep washing dishes in dirty water.

Common causes

In the overwhelming majority of cases the cause is exactly what it looks like:

Clogged or dirty fine/coarse filter assembly at the bottom of the tub
Food debris or a broken glass fragment blocking the sump area under the filter
Secondary blockage in the drain hose or drain pump if the filter is already clean

What you can check yourself

This is one of the few Bosch codes meant to be a routine homeowner task rather than a repair:

Pull the bottom rack, twist and lift out the cylindrical filter assembly at the bottom of the tub
Rinse the filter under running water and scrub with a soft brush and mild soap to remove trapped debris
Wipe out the sump area underneath where the filter sits before reinstalling it
Reinstall the filter making sure it locks/twists fully back into place
Run a normal cycle to confirm the code clears

Call a professional when

If the filter is clean and reinstalled correctly but E22 keeps returning, the blockage is likely further down in the drain hose or pump and is worth a technician visit.

Bosch dishwasher codes hub
Bosch E24 — tub draining too slowly
Bosch E25 — drain pump physically blocked
Dishwasher Not Draining

Sources

E22 Bosch Dishwasher Error Code — Bosch U.S. owner support

This site is an independent reference, not a substitute for a licensed appliance technician or electrician, and is not affiliated with Bosch, Samsung, LG, Whirlpool, KitchenAid, or any other manufacturer named here. Dishwashers combine mains-voltage electrical parts with water. Always shut off both power and the water supply before opening the tub, pump, or heating element housing, and if a repair goes beyond checking filters, hoses, detergent, and visible debris, call a licensed technician.