Hi, it's been a while.

I'm installing a washing machine in a new location and my question is how to discharge it. The wall beside it contains the drain and vent stack for the bathtub.

Can I put a "Y" in the vent stack, a 45 degree elbow to turn vertical, and then a large pipe like a 3" pipe to accept the discharge hose from the washer? Will this work? Will some of the washer discharge trickle into the tub?

Thanks,

Glenn

Hi Glenn,

Sorry, but I would NOT recommend it, for three reasons:

1) The bathtub drain is a 1½" pipe, while washers (especially newer ones, with more powerful discharge pumps) generally need a 2" pipe. And even though washers can often be made to work properly with a 1½" line, your case is different because of my second reason:
2) A bathtub line gets full of hair matted with grease from soap. A washer line gets full of detergent residue and lint clogs. Put the two together in the same pipe - especially a skinny lil' 1½" pipe - and you're going to spend a LOT of [un]happy weekends snaking out that line in the future.
3) Tapping into the bathtub's vent line and using it as a drain line would render the bathtub's trap improperly vented, which needless to say is not kosher.

Sorry I couldn't be more positive about it. Any more questions, we're as close as a click.

Cheers,
Moishe
Note: if this post was helpful, please rate it by clicking "Comment on this Post" in the upper-right corner of this post. Thank you.