Hi, My washer drain pipe keeps overflowing. I tried snaking it but a clog does not seem to be the problem. I think it may be the setup. If you look at the picture originally the standpipe was 9 inches (which was only slightly longer than the pipe leaving the trap) I thought this maybe be the problem so I extended the stand pipe by 24 inches, but this has not helped at all. Seems as if the water is getting stuck at the trap not sure though. Any suggestions? Thank you in advance!