Bosch dishwasher (by 2 users)

Good news is, this is unlikely to be expensive.

Need to sort out where it's coming from first.

Find a stopvalve you can use to shut off the water supply to the machine - there's probably one where the dishwasher is connected to the domestic plumbing. If turning this off stops the water coming in, you probably need a new inlet valve. The ones on dishwashers are generally pretty cheap to replace.

If shutting the water off doesn't stop the inflow, then the only place it can be coming from is siphoning back in from the drain. There's supposed to be either an air gap or an anti-siphon valve where the dishwasher's drain hose goes into the domestic drain. If this gets blocked/stuck, then it can cause dirty water to siphon back into the machine. Check and clear as necessary, then run the machine through on the hottest, longest cycle it's got (in the expectation that not all the water that was sucked in from the drain necessarily started out in the dishwasher).

A.