Washing Machine Drainage into Tub Overflow Pipe

[River432]

Hello Everyone,

I am new to this site and hope someone here can help me out with some information and advice. I am trying to hook up a new washing machine (and a dryer) in a pantry where there was no washer before. I am lucky in some sense because there is a tub/shower on the other side of the wall. I have already tied the hot/cold water lines for the washer to the tub lines which was no problem. But regarding drainage for the washer, I would like to tie into the tub overflow pipe that is also right there at the wall. This 1 1/2" overflow pipe leads down to a 1 1/2" p-trap just below the tub. Also, a 1 1/2" verticle vent pipe connects right before the p-trap.

Questions:

1. Is it possible to tie into the tub overflow pipe for drainage for the washer? If so, can the same p-trap be used for both the tub and the
washer and have both properly vented as well? Or does the washer require its own separate p-trap and vent?

2. Although everything at the tub is 1 1/2" pvc pipe, should I use a 2" standpipe for the washer and how long? (Do you measure the standpipe
from the floor?) And should the p-trap also be 2" if needed for the washer?

Thank you in advance for any assistance you can provide! River432

[hj]

IF you can figure out how to make a washer connection to the overflow, you would not need another trap, and using 2" would also be useless. The standpipe would have to be as high as the washing machine. If the tub drain is all 1 1/2" which is a possibility, then be prepared to have wash water in the tub everytime you wash clothes. In other words, it is a "bad idea".

[River432]

Thank you for responding hj. Are you saying that drainage for the washer requires all 2" pvc pipe to include a 2" standpipe connected to a 2" drainage pipe? If everything around the tub is 1 1/2" pvc pipe, is there anything I can do for proper washer drainage? Thanks again, River432

[kreemoweet]

What you need is to install a proper 2 in. drain for the washer. You can't just add plumbing fixtures without
providing drains for them. Modern plumbing standards call for a minimum 2 in drain for washing machines - all
of it.

[jimbo]

Code requires a 2" drain for WM, and also prohibits the washer sharing with any other fixture. ALSO, we understand than in Massachusetts, the fine for working on this yourself in any way is several thou

[River432]

Thank you for all the responses. I appreciate it. I think I'm just going to hire a plumber to find out if installing a drainage system for a washer is at all practical in the location that I want it (pantry). The washer would be for a rental property in NJ, but I assume the code might be the same as in MA. Anyway, the main laundry room is downstairs off the garage and probably a good 15' from the pantry. The only 2" pvc piping may be at the laundry room location. So, I have no idea how this may be done properly and per code. Any ideas? Thanks again, River432

[Terry]

It becomes a suds control issue, and a backing up issue.
Also, when the p-trap is located below the floor, that makes the standpipe too long, which in itself can siphon a trap dry.
Code requires that the p-trap be on the same floor as the washer and limits standpipe length.

[River432]

OK. I have no problem adding a 2" standpipe with its own 2" p-trap for the washer. But I assume it's all moot if I can't tie into the 1 1/2" overflow tube for the tub for drainage. Correct? If not, then I guess I have to tie into a 2" drain pipe somewhere else, if it's at all practical. If the only 2" pipe is 15' away at the laundry room below, then it might not be worth it. I really don't want to rip up the whole house to accomplish this. Thanks again, River432

[hj]

There may be several 2" pipes you could connect to, but since we are not there to check things out, we cannot be sure, and in many cases, the vent can be more difficult to configure than the drain, because, in most cases, you cannot just insert a tee into a verical pipe and call it a vent.

[Gary Swart]

A basic rule of plumbing a drain is you can not go from a large size pipe to a smaller size. I don't know the NJ rules regarding DIY plumbing, but if this is for a rental, I think it would be foolish on your part as a novice to DIY this job even if NJ rules OK it. You don't want a plumbing problem in a rental in the first place, and one that is many miles from home could be a disaster.

[Terry]

But I have used a 2" standpipe into a 1.5" trap for a washer. You're talking pretty clean water out of it. It's a bit like dumping your washer into a laundry tray. Not something and inspector would jump up and down for, but it does give a bit of cushion when the washer is pumping out.

If an inspector is looking at it, it has to be right. He has to answer for it.