Please help, Washer drain problem!

[MStewart]

Hello, I must say you have a very informative forum, so I sure hope you can assist me with my problem. We purchased our home nine years ago and it was about nine years old then of course the inspector found no faults, but I swear it was plumbed by a complete idiot! All water supply lines 1/2 in non of the outside taps afixed to the studs so when you try and change a faucet it just twists the pipe off in the wall, this is a little background for my problem. Problem- when we bought the house we never had any problems for at least 4 to 5 years then we started getting a strong septic smell when we ran the washing machine, there is no floor drain in this room just the wall drain for the washer. So after a while we had enough of this horrible smell every time we did a load of laundry and called out a local plumber he said the washer drain trap was set to low it measured 38in from top of drain to the bottom of the trap and it should only be 24in thus when the washer drained it flushed the trap of water and allowed the smell to be emitted. So of course I asked him for any solution to the problem, he said maybe try sealing the washer drain hose to the top of the drain pipe this might stop the smell from getting out. So I tried this with no noticeable results, so I cut a hole in the wall and cut the drain pipe down to 24in and resealed the lines together but still no difference. How can this be?? shouldn't the natural U in the washer drain line act as a trap? I am just at a complete loss here, one final note this is a septic tank system and I have it pumped every two years. Thanks for any advice on this problem.

[phishfood]

I would call around and find a plumber that is experienced with smoke testing. Smoke is put into the drainage system under slight pressure. Any opening in the drainage piping will leak smoke, allowing the plumber to locate it.

Edit to add: Have you tried changing the discharge hose on the machine? Though I have never seen it, I have heard of the corrugated hose getting crud built up in it and smelling.

[MStewart]

Thanks phishfood that a good idea, as far as the hose we have cleaned the washer from top to bottom so we know that not the problem. Like I stated before wouldn't the u in the washer hose act as a trap? This is just the most puzzling thing ever and not to mention the most annoying for that I sure welcome your input thanks again!