I’m stumped on this one. A person I know is having a problem with their plumbing and emailed me some pictures. As you can see from the pic he has foam coming out of the floor under the toilet. He said the toilet sits tight to the wall and we know the wax ring seal is broken. There’s no water, just foam. He’s been in the house for awhile and this is the second or third time this has happened. The house is on a slab. There is a second floor bathroom directly above this one. The laundry room is on the other side of the house (maybe an addition, not sure) that is discharged by a injector pump. I believe this happened when doing the laundry. If water was with the foam than I would say the system was clog and needed to be snaked. He’s going to replace the wax ring and re-seat the toilet. Has anyone seen this before? Why just foam? Thank for any insight.