Cross Connection - Syphoning

[RaphDuch]

Thanks for reading my question. I am wondering, if a washing machine is draining into a laundry tub, and the water in the laundry tub fills past the washing machine drain hose (so that the hose is submerged in the water), what is the likelyhood that the washing machine will syphone the dirty water back into the macihne?

Thank you

[Whitegoodshelp (Andy)]

Hello, It sounds an unusual way of running a washing machine. Without knowledge of exactly how it's set up I can't say, for example how much higher is the laundry tub and is there a hole in the laundry tub for the water to drain away or does it fill up - and if so how do you empty all the water away when it's finished?

In order to siphon into the washing machine the water would normally need to be higher than the level of the water in the tub or at least have a straight run down the drain hose. Sometimes water from a sink can siphon into a washing machine if there is a straight run from the sink connection down into the pump, but if the drain hose goes up before it goes down to the pump siphoning doesn't occur (as shown in item 2 on this page 5 things to check for after connecting a washing machine.