I am looking to purchase a house where the location of the washing machine is such that the drain needs to pump water to a location higher than where the washing machine would sit.
The existing drain line has a one-way flow valve installed about 2-3 feet beyond the point where the washing machine would connect to the drain. That 2-3 feet is a vertical pipe so it would seem that the water in that pipe is at risk of draining back into the washer.
We have had a general inspector and a plumber look at the setup and they both claimed it was odd and I should install a separate pump system to make sure no water drains back into the washing machine.
I've never actually owned a washing machine before, do most washers have a pump in them already? Are there special models I should look at? Or do I need another system that can prevent the back-draining?
Realized I do have a picture: