Gas smell when run washing machine

[MNrealtyguy]

Hey folks,
Whenever I run my electric washing machine, I get a sewer gas smell. I think it has to do with the black abs pipe that comes up the right side of the laundry tub (check out pics). My thought is that there's probably no water in this pipe, so gasses may be coming up through the p-trap. I don't really understand the purpose of this pipe and if it's necessary. Do you guys know why this pipe is there and if it makes sense to remove? My other thought was that maybe the washing machine hose is supposed to go in there but when I manually pour a lot of water in the pipe it overflows so I don't think that would work. Any guidance is much appreciated...

[sokoloff]

The water in that black P-trap will eventually evaporate, allowing sewer gases to pass and enter the house. Pour water into the pipe to refill the trap periodically.

In all likelihood, the washer was supposed to (and probably originally did) drain into that black pipe. If it's become partially clogged (possibly right in the trap from lint), you can probably snake it out to clear it and then resume using it as the washing machine drain, which will naturally refill the trap on a periodic basis.

[sokoloff]

Does the sink drain quickly enough to drain the washing machine if you cap off the "washing machine" black pipe (or after you fill the P-trap with water)? If so, you should be able to make the washing machine drain work.

If the sink drains slowly when you cap off the washing machine (or fill the P-trap), you have an obstruction in the line or a problem with the venting on that DWV system. Standard troubleshooting for slow drains would be appropriate.

As far as removing it, you could. (It's not legally the vent for that sink.) But, I'd rather see if I could get it work correctly than to remove it.

[CowboyAndIndian]

I had the same issue. In my case, I had pushed the plastic washer drain hose too far into the outlet pipe.

So far, that it seemed to have gone thru the P-joint and hence past the water trap.

Try pulling out a little ....

[MNrealtyguy]

sokoloff: That's a good idea. I'll try snaking out the pipe and using just using the pipe as the drain as it was originally intended, and keep an eye on it when I do my next load.

Cowboy: I don't think that's the issue in my case, but I appreciate the response.

Thank you both!

[Dicey]

sokoloff: That's a good idea. I'll try snaking out the pipe and using just using the pipe as the drain as it was originally intended, and keep an eye on it when I do my next load.

Cowboy: I don't think that's the issue in my case, but I appreciate the response.

Thank you both!

Oh, please test it manually before you run a load! If you have a watering can or large pitcher, dump a generous amount of water down it before you re-connect the washer hose. If there's some other problem, you do not want to discover it when the washing machine is draining.