I want to add a sink to my laundry. Currently the only plumbing in there is for the washing machine to drain.

I'm hoping I can tee off the water inlets for the washing machine to feed both the sink and the washer, and also drain the sink into the washing machine drain plumbing somehow.

I'm getting conflicting views about what will work. Some have told me the washing machine will flood the sink, others say not, because the newer front loader I'm getting uses less water, and if there is any backfill I can just put the plug in the sink to stop it.

To get the sink its own dedicated drain I've been quoted $1,100, which is just outrageous, to glue some pvc together and patch up some drywall. It's costing me less than that to have the whole laundry enclosed, dry-walled, door installed and painted.

Any guidance is appreciated.

Thanks.

Take a pic of the area and post using, co advanced/manage attachments.

Do you have room for a double-sink?

Are you against a single sink and the washer draining into it?

What size is your drain? OD would be fine. Just list as ~1.125" OD

PVC?

Uder slab? What's under the floor? Access?

Venting?

If I were faced with your situation I'd do it the easy way. I would tee off the washer supplies to pick up the utility sink faucet. I would then pipe 1 1/2 or 2" to the washer standpipe through a sanitary tee (No trap on the sink but I would install a check valve on the sinks drain line to prevent any back ups in the sink while the washer's dioscharging. The washer stand pipe trap will service both the washer and the sink.
This may not conform to code in your area but it's the easiest way to go. Good luck, Tom

Thanks for the inquiries KISS, but speedball1 has the info I'm after.

Speedball1, would this be the kind of check valve I'd use?

http://www.lowes.com/lowes/lkn?action=productDetail&productId=166711-185-024%20LCV-112&lpage=none

And the sanitary tee?

http://www.lowes.com/lowes/lkn?action=productDetail&productId=23396-1814-PVC%2000401%20%201000&detail=&lpage=none

The washer standpipe is 2" and the fitting for the sink is 1.5".

Is there anywhere in particular I should tap into the washer standpipe above the p-trap, like a certain height?

I'm really grateful for this info, as it turns out there's no way I could have afforded to have a plumber put in a new drain, which may be the correct way, just not the affordable way.

Thanks.

Tom gave you excellent advise...

Water: you can actually buy double outlet valve and install it on existing w/m valve.
Drain: do as Tom said - or cut open wall and connect sink drain low into w/m vent. In this case you would need to also install trap under new sink.

I have seen it done this way many times and it worked just fine.

In this case you would need to also install trap under new sink.

It's not often I disagree with Milo since I consider him to be better up on the newer stuff but in this case he's recommending double trapping the sink and that's a no- no.
By connecting into the washer standpipe you're using the standpipe trap for both fixtures. See the bold letering in my last post.

Speedball1, would this be the kind of check valve I'd use

And the sanitary tee?

The washer standpipe is 2" and the fitting for the sink is 1.5".

Is there anywhere in particular I should tap into the washer standpipe above the p-trap, like a certain height?

Yes on the check valve and use a 2 X 1 1/2" Sanitary Tee on the stand pipe. I woul keep the tee on the stand pipe as high as I could. Good luck, Tom