standpipe drain backing up

I have an old house (1940’s) that I rent out to a family in Amsterdam, NY. Before my purchase of this property in late 2007, someone tried to install a set-up for a washer and dryer. The electric for the dryer had to be changed to code and now, the washer drain stand pipe (always backed up waste water out the top) needs attention. The 2 inch PVC stand pipe is connected to a 1.5 inch metal pipe with no P-trap running straight to the sewer line. I know that I have to install a P-trap to stop the sewer gasses but because I have no way to remove the 1.5 inch metal pipe, I’d like to know if I could somehow reduce the waste water flow pressure from the washer as I believe that is why the water backs up. I’ve snaked the pipe a few times and it seem to be clear. I used a heavy duty “spade tip†snake. Any suggestions?

Gary

Multiple problems, you must both have a trap, a vent, and, with many modern washing machines, a 2" drain (2" is required on today's codes). The new ones tend to just pump the water faster than the old ones...not much you can do about it. An alternative would be to dump it into a sink, then manage some way to then get it out of the sink, using it as a temporary storage.

The drain just has to go into a 2" or larger drain without a restriction. And, as previously pointed out, the standpipe must have a P trap and be vented. You might be able to slide by with a Studor vent, but that may or may not be kosher where you live.