Hi smartlydia, I'm assuming that you've had both the washing machine and dishwasher for a while and have not added either a new washing machine or dishwasher. If this is the case then do you run both machines at the same time? If you do and this has never been a problem then let's move on. Have you checked the waste pipe(s) from both the washing m/c and dishwasher for blockage (especially at any bends / traps)? As you haven't mentioned it I'm also assuming that when you run water directly from the sink it runs away easily without any problem. If this is the case then as the sink, washing machine and dishwasher usually all end up in the same waste pipe a frozen pipe doesn't seem likely to be the problem. Not sure what else to recommend. I hope if nothing else this gives you something to try that you haven't before.
Gray
January 2010