[cam1700]

What are the rules in terms of vents/traps if I were to create an opening using a wye off a bathtub drain before the trap?

I want to create an opening to drain a portable washer so the branch will literally be just an opening to hang a hose down it.

Assuming the bathtub is properly vented, will this create any problems?

The link below has a picture of what the drain is typically supposed to be (i.e. into a sink)

http://ecx.images-amazon.com/images/I/61ypFshEXfL.jpg

[massplumber2008]

Hi Cam

The rules are real clear on this... you CANNOT do what you propose. Not only is it not allowed, but the tub is a flat surface fixture that will only accumulate all the water that you try to direct down the small bathtub drain. This will not only make a mess every time you drain your washer, but will also lead to increased clogs in the tub drain piping!

If your sink drain is 2" you may be able to connect into that drain IN THE WALL, do some vent work, and then you may be all set here.

Mark

[cam1700]

Thanks for the reply Mark,

In a different configuration:

If I were able to create a new branch off the drain in front of the tub's trap and add a 2nd trap for the washer with a proper standpipe, would they be able to share the same vent?

(Keep in mind in Ontario, Canada, the minimum drain size for a washer is 1-1/2", not 2")

[massplumber2008]

What you propose is referred to as WET VENTING a fixture. In some states (not all) wet venting is allowed, but I don't know of any states that will allow a washing machine to be connected to a wet vented fixture (tub in this case). Here, the sheer volume and velocity of water discharged from a washing machine is so great that it can siphon off the trap of the wet vented fixture (tub) and allow sewer gasses into the home... a definite health hazard, for sure! I just don't see how this will work for you, but you never know it could be allowed in Canada and I'm afraid I am not up on Canadian codes... call local inspector to be sure, OK?

Now, if you could individually vent the new trap off the tub drain and connect that vent into the tub vent at a minimum of 42" above the floor then that would work for you!

Otherwise, I'd use the sink drain and cut into the drain just below the sink drain connection in the wall and run a new vent/drain up and connect the vent back into the sink vent at 42" above the floor.

Sorry to say, but this is how plumbing design/engineering principles work!

Mark