We have been having issues with the dishwasher filling up with waste water when off - particularly when running the washing machine.
The plumbing under the sink looks as per the attached photograph and as you can make out, the waste pipe in the wall is very high meaning that almost the whole lot of pipework is constantly full of water.
Im guessing that what happens is that the discharge pressure from the washing machine (on the left) is high enough to climb over the dishwater high-loop and into the dishwasher - as the resistance going up to the waste is quite high.
How do we best solve this, without the significant operation of lowering the waste?
-In line Non-return valve on the dishwasher hose?
- re-jig of the pipe work to make the rise to the waste less dramatic?
