Our washing machine is in the basement (of our 100 year old row home). We also have a half-bath down there. When the washing machine is draining, the water backs up into the sink of the bathroom and overflows. Any suggestions? A previous owner put paneling up against most walls, so it is difficult to see a lot of pipes, wires, etc. Thanks
You may be able to snake the drain and make it work,
Or you may need to pull the paneling and get to the problem, if it's piped wrong.
The washer should be run in 2" and the p-trap needs to be vented.
The standpipe coming off the p-trap needs to be at least 18" long.
If the existing pipe goes into a cast fitting, often times they are a 2" hub, in which case, you can bump the size up to 2".