Moving laundry room to garage, Drain?

[jamescustom]

How do I tie my new 2" washer drain into existing 1 1/2" bathroom sink drain under bathrooms?
Can I "Y" joint into the sink drain and replace the last section of 1 1/2" with new 2"?
Or do I have to increase to 3" from "Y" to the stack?

My girlfriend and I just bought a 1968 single story home with a crawlspace and are going to remodel the kitchen, laundry room and bathrooms. We are moving the laundry room from the kitchen to the garage. I have rough framed in a new 7' by 9' room in garage and raised the floor approx 6" to match floor with rest of house. All ready to start putting in the drain system.

Washer will be sitting on an exterior wall so I will vent straight up to roof. I plan to run a new 2" drain through the crawlspace across the house and tie into existing drains under the bathrooms, approx 25 ft away so I need about 8 inches of fall. There is a 1 1/2" drain from bathroom sink that is in perfect spot. I'm pretty sure I can "Y" into it easy enough and run new 2" from "Y" to stack, but will 2" be big enough, or do I need to increase it to 3" or whatever?

I've already opened the city permit and waiting for approval so it will be inspected, which is a good thing. But I want to do it right so the inspector doesn't have any problems with it.

Thanks for any advice you can give me.

 

[CT18]

I would check local codes in your area. Where i am washer box needs to tie into 3" stack.

 

[journeyman]

You cant run a bigger drain to a smaller on. If you are going to run 2 inch which is code then it needs to tie into a 3 or 4 inch drain

 

[phishfood]

I don't know Washington state code, but here you need a 3" stack or branch drain to attach the laundry drain into.

 

[jamescustom]

OK, that makes sense. I don't want to cut into the 3" stack and replace the 3"x3"x2"x1 1/2" Tee (see attached pic) that is there because I'm not sure I have the space to do it, even if I use a 3" banded coupler.

So my next idea is to run my new 2" drain past the big Tee and "Y" into the 2" drain on the other side that is coming from the kitchen. Basically making my drain make a 180 deg turn back into the big Tee (see attached sketches)

I think I can still get the slope I need but just barely. Is this acceptable?

 

[jamescustom]

Sorry pictures got turned upside down and are not very good quality but hopefully I am getting the idea across. Thanks for your help.

 

[CT18]

i believe there is a max distance that 2" can be run. You will have to check your code. I have been doing industrial large commercial for many years now so i am not sure.

 

[jamescustom]

I'm not sure what the max distance is but i called a local plumbing company and they said 25 ft was ok. Haven't been able to verify that with inspector yet.

 

[breid1903]

if you are going to get a permit, well get it. then call for an inspection and ask what they want. what they want is what they get. since you are asking us how to do it, may guess is the you haven't meet the inspect.

if not permitted, well do what you want. if the drain is not proper sometimes they will NOT handle some of the newer washing machines. since you putting this in the garage, well if it pucks it's in the garage. no harm, no foul.

peaceup raz

 

[mfg2414]

I know this is a little late but the information will be good. The thought is what might happen if there were a clog. It has always been my practice to keep the washer on its own line. If there were to be any clog the washer has the power, if the drain line is snug in the standing tube, to push that water back into the sink. If it were a dishwasher that is not very much water. In a top loader they can hold as much as 25 gallons. Way more then most sinks can handle. If you have no choice and the sink must be in the line be sure to put in a back-flow trap so this can not happen in your house.

 

[Matt30]

I'm not sure what the max distance is but i called a local plumbing company and they said 25 ft was ok. Haven't been able to verify that with inspector yet.

25 feet is ok only after a vent has been taken off. 2" you can only run 8ft before until you need a vent. Some inspectors might require an additional vent for a run that long.

 

[jamescustom]

Sorry I took so long to respond, had to put house remodel on hold for a couple weeks. I work construction and we just started building a new 2 story ICF house with round rooms... fun fun. So trying to pull double duty after working in this heat all day is tough.

Anyways....

Yes I do have permit approved. I haven't called for inspection yet, want to have it correct as possible before he comes so I don't have to pay for a 2nd inspection.

Still haven't verified if I need a 2nd vent for long 2" drain run, but I am prepared to put one in if required. Plan on calling for inspection early next week. Right now I'm trying to figure out the electrical ...... UGGGH! I though plumbing was tough.. lol

 

[Matt30]

Why not go above and beyond and run the extra vent so you are covered? It's only going to help performance of the drain, and cost will be minimal.