I will try to explain the set up.
4 Unit building, 2 1000 gallon septic tanks.
Large P trap on washing machine (little larger than height of washing machine)
P trap then connects to a horizontal PVC pipe via a double/”v” shaped PVC fitting, the right side of this connector has PVC running to cast iron drain pipe which I believe is the Kitchen sink of unit # 1. The left side then connects to the large cast iron drain pipe that goes to the septic tank
To me it appears that since this “v” is positioned as if it was lyng flat on the table (i.e the line fron the kitchen sink and from the Wash P trap enter at the same level)
My thought was that water would from the kitchen sink ended up routing to the washer. However, Unit 1 is currently vacant and washer has been full several times
Therefore, my guess is that the septic is backing up entering the horizontal pipe described above and continuing into the p trap and into discharge hose.
Any ideas? Maybe just need to pump septic tank, but want to make sure this is the problem. Also, any advice on checking the level of the septic tank.
Maybe I could place discharge hose into a bucket and see if is actually septic tank back up. I haven’t notice a terrible smell yet.
Thanks all