Oh I could go on about this one a while but the photo says it all. One of our technicians went to inspect a dishwasher last week, reported to be not draining. At least fifty percent of the dishwasher call outs we go to are for drainage issues, but when he got there the sink was overflowing. So he delved into the cause and pulled this DrainBurg out of the plumbing!
Dishwashers drain into the same plumbing as the sink through a small drain spigot on the side of the main pipe, so this was completely blocked. It is easy for the spigot to become blocked as it is very slim, but not so usual to find a living, breathing DrainBurg.