Tiny sink, tiny bathroom. 2" cast iron right there. Any reason not to use rubber T?

[CanOfWorms]

There are 6 sinks, two tubs, three toilets in this house that's 110 years old with only one vent pipe sticking out the roof... no sewer gas problems so far. I think I'll just hook it up to the same lines that the washer drain is hooked up to and see what happens.

[mtcummins]

Jim is a respected member here. He is trying to explain to you why your idea won't work. You clearly don't want to listen, just want someone to tell you to do what you already intend to do. That's not the point of this forum. We're here to tell you how to do it right, and tell you when your idea is wrong.

You're backcheck/extra pitch/etc ideas will make your problems 10x worse. You're going against not just code, but basic fluid dynamics.

You need to get a vent into this setup. Use an Air Admittance Valve if you absolutely have to, but don't just skip the vent. We're not talking about "code scmode" here, we're talking about serious health risks. Just b/c something you do seems to work (which just tying into that line very well may appear to be "working fine," doesn't mean that its working safely.

Ultimately, the advice I would give, and this is also coming from someone who doesn't hold the code in particularly high regard but cares about doing things at least as close to "right" as possible, is that you either need to learn a LOT more about plumbing before taking on this project, or call a plumber.

[CanOfWorms]

I got it. I was actually changing my reply to something a little less heated as you posted this.

About 6 feet away there is a slop sink and washer drain hook up. Tapping into that seems to be a better option

[mtcummins]

is this setup vented? If so, you can tie in your drain line to the line you wanted to before (don't do the pitch thing, come over and tie in with a PVC SanTee, not the fernco thingy), and then bring up a vent line to at least 6" above the flood rim of the highest fixture in the room (typically 42" works) and tie the vent into the existing vent using an upside-down santee.

[jadnashua]

110-years ago, they used S-traps and relied on a single, often quite large, drain to act as the vent. They were still doing this in the 1950's, as my mother's house is built like that. 110-years ago, the only plumbing in the house was maybe one bathroom and a kitchen sink. It worked. Today, after modifications, adding yet another bathroom is just not going to work well.

A single vent pipe through the roof does not imply that what's there couldn't be vented properly...there are many code-compliant ways to combine vents, but as I said, you cannot combine FUNCTIONS of the piping if you want it to work. Getting things to drain often isn't the issue, it's that they drain too well and siphon other traps dry, or, you end up with backups.

Code assigns each type of drain a certain fixture unit...the amount of fixture units determines the size of the vent(s) and the drain line(s).

You need to figure out which pipes are drains and which are vents...it may be that everything is wet vented except maybe the top floor.

[CanOfWorms]

what is there right now is really complicated. here is a sketch. Keep in mind this is only one half of what is down there. On the other side of the basement near the main cleanout there is just as much.But all that is drains directly into another 4" and no pipes connect from here to there.
What do you think about tapping into the right side washer drain exactly 49" from where the sink drain? This is a small sink that will be for occasional use. Attached also is the existing room and the sink I want to install.

[asktom]

Well, the advice went silent. That is because, while what you want to do can no doubt be done according to code, you really need a qualified person on site with eyeballs to tell you how. It is too complicated for this forum. You may also have turned people off by saying, "code schmode", or whatever it was you said. I think that is the deal.

[Terry]

My first instinct is to say code shmode. : )>

Well I just got back from India yesterday where they also think like that. It's nice to be back in the USA where we have plumbing inspectors.
I can drink water all day now without getting sick. I'm not saying I didn't enjoy India, I did! But it's nice to be where we have working codes to protect "investments" and "health".
Nobody will want to buy a home that has been hacked up by someone who's first instinct is to say code shmode. : )>

Here is a nice link to Bert Polk's plumbing tips

[CanOfWorms]

Well code schmode within reason. Sorry if I pissed anyone off. Did you use any Idian toilets? AKA a hole in the floor.
It's pretty clear from a recent investigation that the line right there, the blue line in the sketch is a dry vent line, not a waste line. If I tap into the washer drain line 50" to the left would that be vented?

[mtcummins]

IF that is indeed a dry vent, then it would be vented if you tie into it at least 42" above floor. What we can't really say for sure from this info is that it is indeed a dry vent, and that that dry vent has enough fixture unit capacity left to handle another lav.

You should probably consult with a plumber on this. See if you can find one who will take $100-150 of your money to take a look, and tell you exactly how to do it. It's worth the cost to ensure you're working safely. He'll be better able to advise you, as this is a bit too complicated for us to tell over a forum.

[CanOfWorms]

Well, the second floor sink wasn't draining. When I tied snaking it the snake went up instead of down. I thought the sink was connected to that blue line in sketch. There is a rubber boot prrior to where it.goes up to second.floor. but when I opened it up it was bone dry and there was no residue or buildup in the old metal pipe at all. I ended up using that hard core sulphuric acid drain cleaner on the sink.

[asktom]

You seem to want to do the job correctly, given that you are still posting, but, without some qualified person there in the flesh it probably just isn't going to happen. I'm not sure if you are going to find a plumber willing to explain how to do the job, most want to do the job and could probably do it in less time than they could explain it clearly. You might be able to work with a plumber as far as the demo part goes. I'm hoping you will get a qualified person to do the drains for you. If not, I hope we at least talked you out of the rubber tee.

[CanOfWorms]

You have talked me out of the rubber Tee and talked me out of just piping into any old pipe. I'm not as thick as you might think.
I really do appreciate all your help and advice.
I am cash poor and time poor. This project isnt the most important at the moment.
I can't really afford to get a plumber in just to look. I will likely run into one in my travels that will give me a little free advice. Things like that happen to me.
I actually found some piece of HVAC dignostic equipment in a case on the side of the road about 2 months back. I looked it up and it's about $250 new. I might post an add on craigslist to trade the equipment for service.

[asktom]

If this is a back burner project and you now have a better picture of what is involved, that is a good thing. You can keep your ears open for the right opportunity to get help and have some idea of what is involved. Happy Plumbing.