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Old 01-05-2009, 08:48 AM   #1
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Drain configuration, which should I use?

My house is very small so the number of drains in my crawl space bewilder me, I've got to run a toilet drain into one of them. I've attached a drawing; the lone 3" pipe is from my current bathroom, and my kitchen sink and washing machine feed into the 2" pipe. The boxed in area is my utility room on the first floor. We're adding a bathroom upstairs above this room and I need to run a new drain from the second floor. Here's what I've got:
-all cast iron drain pipes (original from the 40's)
-a 3" pipe that comes 1/2" above the floor in the utility room, 12" off the wall, but is plugged and unused
-a 6" pipe in the crawl that has only the furnace drain into it
-house is over a crawl space, all pipes go below ground before any joints

I see three options and need some feedback:
1. Bring drain into the utility room, use elbows to run into the existing 3" pipe. Problem I have here is that my stacked washer/dryer sit over this drain. Its at least a foot off the wall so elbowing to it would be ugly and I'd have to elevate the washer/dryer that much to run the drain pipe underneath.
2. Cut the 3" pipe off in the crawl, run new drain into the crawl and connect there.
3. Run new drain into the crawl and feed into the 6" pipe.

Thanks for any feedback!
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Last edited by moneymgmt; 01-05-2009 at 09:11 AM.
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Old 01-05-2009, 10:09 AM   #2
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You need a permit and inspections from your local Building Inspection Department for the work that you're proposing.
1. Without seeing it, my guess is that the 3" pipe w/plug is actually a main drain line clean-out access.
2. Probably your best bet and don't forget to replace the clean-out.
3. This 6" line may well just drain condensate to a dry sump or to a storm water only drain system, so unless you're certain that it goes to the sewer, don't tap into it.
Good luck!


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Old 01-05-2009, 10:28 AM   #3
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Initial assumption was that the 3" pipe was meant for a second bathroom, but this house only has 750sf on the first floor and that drain is less than 2' from the side entry door..... so probably not originally for a bathroom (plus it isn't a toilet flange). I've dumped several pitchers of water down it, and based on the smell coming from it, it ties into the main drain. No idea what it was intended for but I live in one of those cookie-cutter house neighborhoods and every house I've visited has it, but everyone has a rag shoved in it with either the washer or dryer over it

Good thought on the dry sump, hadn't thought of that. Only thing that goes into it is a 3/4" furnace drain, and with only 3' of headroom in the crawl I'm not sure I can get in there with a hose to try filling it and see what it does.

I've been reading posts on cutting cast pipes, does it sound like a viable option to cut the 3" pipe in the crawl and tie the PVC to it there?
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Old 01-10-2009, 09:10 AM   #4
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Yes you can cut into that line quite easily, and then using no hub band to attach new fitting...good luck
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