Tub backing up!!!

[pooky85]

I just noticed that when my washing machine drains water backs up into my tub. It's not a lot of water, probably a gallon or so, but still, it shouldn't be happening.

OK, a little background:

The tub and shower are on the same level and are literally back to back (main floor laundry put in a closet by PO).

The pipe coming up to the tub is 1 1/2" black/galvanized that has been spliced with a pvc Y that has been fernco'd to the galvanized. The branch off of the pvc Y is level to the "existing/old" pipe, BUT the branch is the side that the washing machine drains into, which also happens to be the more pinched/restricted side of the Y. Also, it doesn't look like the pipe is sloped very much, but the tub drains ok.
The pipe is also vented to the roof about 3' away from the Y.

I'm not really leaning toward blockage or inadequate venting, but I suppose anything is possible.

Is it possible that I have inadequate sized pipe, especially now that a washing machine is draining into the pipe too?

 

[johnjh2o]

Most codes require a 2" line for the clothes washer. The pumps on the new clothes washer pump the water much faster. Without seeing what you have it's hard to advise you how the solve your problem. A picture may help.

John

 

[pooky85]

I'll get one up ASAP.

 

[Will]

If it's backing up into the tub, you probably got a blockage. Get it snaked out good, then see if that improves the flow.

 

[pooky85]

I'm thinking the 1 1/2" size sounded a bit on the small side, too. Nothing leads me to believe it's blocked up, but anything is possible. If it were blocked up who sells a decent pipe snake? I think I only have about 50' to the main from the cleanout and have been meaning to do an exploratory snake, but haven't gotten one yet. I wanted to buy a 75' hand snake but when I look online at my local "big-box" hardware stores online they don’t list any...