Washing machine standpipe leaking

It's only been leaking a year, and not terribly. I didn't install it and I am just a DIY. I can see water ooze out where the drain hose enters the stand pipe during the exhaust cycles. The guy had a pipe trap at the top of the PVC standpipe that appears unnecessary. I removed it for a few hours and smelled no odor. No lint clogging in the trap. No vent is apparent. The standpipe comes out of the floor from an almost inaccessible crawlspace. The stand pipe is higher than the water level in the machine. It seems that he had a little ring seal around the vent hose on the portion that was stuck in the stand pipe.

Any suggestions on how to fix this or general comments would be greatly appreciated. I am trying to learn as much as I can for future projects.

Water leaking out usually means that the machine is pumping out faster than the drain can handle. This can be the drain too small ( should be 2" but many were installed at 1½") or drain is partially clogged. Code requires the trap to be above the floor. The vent is after the trap, so we can't tell if you have a trap at all or if it is vented.

Thanks a ton for the feedback.

Since it wasn't leaking for the first few years I was there and it's the same washing machine, there's probably some blockage going on? First thing to try should be drain auger? There doesn't need to be a powerful seal where the drain hose inserts into the stand pipe, right?

There should not be ANY seal where the hose inserts into the standpipe. IF he had a trap at the top of the standpipe, you have to check for one at the bottom also. IF there were two traps, that would be the reason for the splashback.

Sel said:

. The guy had a pipe trap at the top of the PVC standpipe that appears unnecessary..

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Please describe that "trap" . Is it an actual U-bend, or simply a "cap" seal around the washer hose?

jimbo said:

Please describe that "trap" . Is it an actual U-bend, or simply a "cap" seal around the washer hose?

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It's a U-bend made with PVC.

Edit: It's actually more of an S.

hj said:

There should not be ANY seal where the hose inserts into the standpipe. IF he had a trap at the top of the standpipe, you have to check for one at the bottom also. IF there were two traps, that would be the reason for the splashback.

Click to expand...

Yeah it was just a plastic ring around the hose. Not sure how effective it's supposed to be, but I read that you're supposed to just push the hose down the standpipe so I noticed it and thought it was odd.

I can't see a second trap. I think there's one under the floor. But the crawlspace is like Mordor and I ain't going down there unless I get desperate ;-)

It didn't leak for the first few years so maybe there's a blockage down a bit?

You do not have to "see" a second trap, just remove the hose and shine a light down the pipe to see if there is water at the bottom of the pipe, or drop a length of rope down it and see if it gets wet.