Plumbing question: adding drain to existing washing machine drain

[elguappo]

My washer/dryer is in the garage, and I want to add a utility sink to wash up before coming in the house.
Only problem is, the only drain out there is for the washing machine, and of course the open hole for that is >4' off the ground.
The utility sink would be on the short side of an L while the washer is on the long side.

My question, finally, is can I cut in a T lower on the washer drain to accept a sink drain from 8' away? I should have enough room to slope it properly.
(I would also T off the hot/cold lines to the washer as that is the only water out there)

Thanks

 

[thrillho]

El Guappo-

I'm sure you'll get a "plethora" of responses, but just in case...

I'm in SD and have the washer/dryer in the garage too. I did exactly what you are describing when we bought our house.

I cut an "access" hole in the drywall to get to the drainpipe and then cut out a section to accept the T (with 45 degree angle) fitting with the hose clamps on it. I'd say that is about 6" from the floor. Since the P trap is pretty low, I wanted to get the maximum slope possible from the laundry sink to the drainpipe. And even at that, the slope is pretty shallow, maybe 10 degrees at most.

Then I just rigged up the drain from the laundry tub to slope down and meet that T fitting. I installed it almost 10 years ago and it's worked perfectly since day one, unlike most of my house projects...

Couldn't imagine not having the sink in the garage, it gets used constantly.

Buena suerte, mi Jefe

 

[Tim The Tool Man]

Depends where the trap is located for the laundry discharge pipe and if you can vent your new laundry tub drain. You don't want to tap in before the laundry trap. You could probably vent with one of those check vents. http://www.mobilehomerepair.com/checkvent.html

 

[Treeman]

I am interested in doing this also. This link (and other threads on this site) make it look more complicated than what you propose to do.

http://www.terrylove.com/forums/sho...-machine-utility-sink-drain-setup-need-advice

It's all about codes and safety.

More comments?

 

[gmwelder86]

You need to cut in a tee before the trap on the washing machine. You can do this by cutting out the most likely 90 that leads to the p-trap on the washing machine stand pipe and replace it with a combo, which is basically a Wye+45. than continue on to the sink. Depending on the distance from your washing machine drains vent you can just wet vent your sink if that is allowable by your local plumbing code. Typically a utility sink will have an 1-1/2 drain, if you up size to 2" you can wet vent. Makes life a little easier as you dont have to worry about A: running another vent through the rough or B: cutting back into your vent stack. Just another way to making this a little easier.

 

[Zeke]

Or just loop a vent around to the one at the washer drain. Any way, you need to vent the sink trap.

 

[elguappo]

The laundry drain is a Y out of a drain/vent stack. That's how they all are in California.
There is no conventional P trap for the washer, just a flexible hose with a stiff gooseneck at the end that slides into the Y stub of the drain/vent. It is not sealed or airtight in any way.
So if I cut in a T 6-12" from the floor, slope my 1.5" drain from the sink around the I side corner and down to the T, it would vent where the washing machine gooseneck goes into the Y, and drain just like the washer.

Hope that all makes sense.

(thrillho are you on the Ars Technica forum? That username is familiar)

 

[MrMark]

The laundry drain is a Y out of a drain/vent stack. That's how they all are in California.
There is no conventional P trap for the washer, just a flexible hose with a stiff gooseneck at the end that slides into the Y stub of the drain/vent. It is not sealed or airtight in any way.
So if I cut in a T 6-12" from the floor, slope my 1.5" drain from the sink around the I side corner and down to the T, it would vent where the washing machine gooseneck goes into the Y, and drain just like the washer.

Hope that all makes sense.

(thrillho are you on the Ars Technica forum? That username is familiar)

All that is wrong. Follow the picture on the above linked Terry Love site.

 

[Ron Lombardo]

...you have to be careful at what elevation you cut a wye and 45 in as a TEE because the laundry machine is pumped and its not unlikely the water will back up in the sink ... if the elevation is too low.

The best bet would be to open the wall and cut the tee in as low as possible on the vertical line and run it over to the sink with a trap.

 

[elguappo]

...you have to be careful at what elevation you cut a wye and 45 in as a TEE because the laundry machine is pumped and its not unlikely the water will back up in the sink ... if the elevation is too low.

The best bet would be to open the wall and cut the tee in as low as possible on the vertical line and run it over to the sink with a trap.

That's exactly what I was saying. Apparently I am not expressing myself properly.
Of course I would have a trap under the sink.

 

[Ron Lombardo]

... couple of things to keep in mind the waste line should be min 2" and if the line is vented properly ... this would be wet vented ...and the arm over to the sink .. there is also a code restriction on its size in relationship to its length. in NY 11/2 can be 42" and 2" 60" ....

 

[camarotoolman]

Run both drains through the outside wall, use that water on your grass.

 

[RCStocker]

Run both drains through the outside wall, use that water on your grass.

You have the best answer yet. When I built my house and shops I got a 1500 gallon ceptic tank and use it for gray water. I put a pump on it to water the lawn.
In California the water cost so damn much it has more than payed for itself after 35 years.

You will not get water back up form the washer. If you do you have a pluged drain line and have another problem to take care of.

You need a separate P trap for your sink. As long as it fits below the botto of the p trap you will be fine. Use a y T so the water is pointed in the down direction. You do not want to run a streight T. It does not meet code.
The only thing you need to worry about is on the second floor and where you connect the toilet drain. If you install the sink dran in the worng place it can **** all the water out of the tub and sink P Traps. There are code requirments for this. The set up may vary depending on how things are connected.

You do not have this problem. Just put in the sink, P Trap and run a lind over .
A 1/4" drop for foot will do just fine for a sink. You should have plenty of room. It does not matter if you tap in above or below the washer drain as long as the opening for the washer is higher that the bottom of the sink. Water seeks its own leval and this way if it does back up the sink will hold the water until you get it unpluged.

Hope this makes sense.

 

[Ron Lombardo]

.... your going to use water from a garage utility sink to water your lawn ?

"you will not get water up from your washer" ...Have you ever heard if SUDS PRESSURE ZONE ? distances and location of the tee are critical.

 

[elguappo]

I need to clarify a few points.
The sink would be on an outside wall, and that side of the house is zero lot line, so my neighbors side yard. Not gonna vent out grey water into her yard.
The wye for the washer is at least 4' high on the wall. Considering the sink is around an inside corner and probably 10' from the drain, the challenge will be having enough slope below he sink to the Tee at the drain. That's 10" slope so the sink will have to be a little high to have enough height.
This is also on a slab so there is no below grade work possible.

 

[Falcon67]

All that is wrong. Follow the picture on the above linked Terry Love site.

X2 - that washer needs a trap, 2" min. I would also vent the sink AND use 2" pipe because the force of water coming out of the washer could easily pull the water out of the sink trap.

Our old house had a 2" drain with no trap. I fixed that right away. The only way to do that one was to T off the vent stack and trap up to the washer on the house side of the wall. Worked fine.

 

[Ron Lombardo]

I ruled out gray water right off the bat on a utility sink.

The wye for the washer is at least 4' high on the wall.... do you mean 4inches ?

... probably 10' from the drain, ... That's 10" slope ... the slope is 10' would be 1/8 per foot = 1 1/4" pitch.

If you can cut the wye in 4" above the slab and run a 11/2 arm 10' its not code but it will work if the vertical pipe is vented ... 2" would work better and I;m assuming the 2" tee for the washer is above the new tee ... not the idea senario ...but will work and possibly any restriction would result in the washer backing up to the sink .... if you want to add a tee at the sink and add a Boca Vent this might help also..

 

[elguappo]

I need to see the pipes, its all behind sheetrock right now, except the standpipe for the washer drain and 2 spigots sticking out for hot/cold for the washer.

I won't know the status of any P traps or vents until I get in there.
Thanks all

 

[Ron Lombardo]

My guess from experience ...the tee for the washer and trap is probably 12" off the floor creating a 3' standpipe for the washer ... your probably going to have to run the waste outside the wall instead of cutting every stud .... i would also assume the 2" waste for the washer is vented ... Calif has similar codes to NY.

 

[elguappo]

I would be running the waste line from the sink to the washer drain outside the wall. Not cutting into all those studs.