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:
Best Answer
Washers have their own pumps. They are designed to pump water to heights "above them" but not generally "designed" to pump a longer run than the approximately 6' drain line they come with.
With that said, they will certainly pump beyond this amount, but based on how you run it, there is definitely a chance that the water that remains in the drain line can feed back in to the washer. This is not an issue if you are using the line the washer comes with. If you extend it, it can be a problem.
Also, with this said, your concern talks about the existing drain. I'm not too sure why there is a one way check valve either, (it is "strange") but it is not there for NO REASON. Either the current owner, or some previous owner had a bad experience with a sewer backing up, and if the sewer drain for this washer is at the "lowest" open point in this home, then the check valve would prevent that backup from visiting the floor via the drain pipe. More concerning is that THIS HOME may have had this issue. I would expect the homeowner knows this but it is possible they do not if the valve was already there. It is also possible the sewer issue causing it may have been fixed outside of the home. (if this is indeed why it is there at all).
Next.... You asked about the washer pump, but please realize that with the check valve there, the sewer wont by-itself back up into the washer. more importantly, since you DO NOT seal the washer drain pipe to the sewer drain pipe, if the sewer were to backup, your washer water and or sewer water would primarily end up all over the floor
If you have a wash basin, you would want to drain the washer into that, and then have a separate pump to drain the wash basin. That might be an ideal solution.