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daniel lane
11-12-2016, 1:17 PM
Hi all -

A quick question. We moved to NC last year and the house we bought is plumbed for a basement toilet; however, I don't see anywhere to tie in a sink. Is this common, or am I missing something? Basically, all there is down there is a 4" PVC pipe sticking 3 feet out of the ground and capped off.

I'm finally looking to get the basement set up for my workshop and would like to get a sink installed for a sharpening station / general cleanup and with this situation, I'm not sure where to start!


Thanks,

daniel

Myk Rian
11-12-2016, 1:33 PM
We found a stand pipe inside the wall.
No wall? I guess no pipe.

The only other thing I can come up with is to cut the floor out, and plumb one in to the existing.

Jim Becker
11-12-2016, 8:30 PM
I agree with Myk...you may need to cut the concrete so you can tie into the soil pipe that's pre-positioned for the toilet. Or install a sink with a pump system that sends the waste water up to existing plumbing overhead.

Clint Baxter
11-12-2016, 11:04 PM
If it is a pipe for a water closet, it should have a vent somewhere. There is often a sink drain plumbed in as well that provides a wet vent to that water closet drain line. If it exists, it may not be close. Regardless whether there is a sink plumbed in, a drain for a water closet needs to be vented. Look for the vent and maybe that is where a sink might be tied in. BTW, the vent for a water closet is supposed to be at least a 2" pipe, so that is one thing I'd be looking for.

If there is a backwater valve installed in the basement, they are often located under 4" pvc piping. But if there was a backwater valve, it is supposed to be accessible, but I wouldn't put it past someone to install a glue cap atop one.

Clint

daniel lane
11-14-2016, 9:38 AM
Thanks for the replies, guys. So the basement is partially finished, the remainder is unfinished "crawl" space. (It's about 9' high, not much need to crawl!) I've not dug through the fiberglass insulation to see if I can find a vent or anything, but that makes sense. I'll dig around later this week. Come to think of it, I can probably follow some of the PEX tubing to see if there is water running somewhere. Thanks!


daniel

Jamie Buxton
11-14-2016, 10:45 AM
You say you want a sink, but have a drain for a toilet. Why not run the waste from the sink into the waste pipe that was intended for the toilet?
And if it really is a rough-in for a toilet, there should be a water source there too. You could run it into your sink. Done.

Now, if there's no water source for the toilet, I'd be skeptical of your analysis that you're rough-plumbed for a toilet.

Marty Schlosser
11-14-2016, 11:44 AM
I agree with Clint (post #4). Here in Ontario, Canada you can legally tie a sink drain into a toilet vent pipe; I believe the technical term is "wet vent".

daniel lane
01-02-2017, 12:54 PM
An update, if anyone was curious:


Digging around in crawlspace, I couldn't find any vent lines. I tried multiple times, but where it would be is very difficult to access due to a buttress wall supporting the corner of the garage slab foundation. (Essentially there's 12" between the framing for the finished basement and the buttress wall, which is 6 feet long, so it's hard to get in there and see behind the insulation.)
I've had a neighbor confirm there is a lower sewer line behind the house (the rest of the house drains toward the street, so sewer discharge is at chest height in crawlspace), so at least that confirms it's going somewhere without a pump.
The city doesn't have any drawings; they would only have had structural, anyway, and the purge after 1 year.

After this, I basically gave up. However, I recently found in the middle of the attic a 2" PVC line that comes up about 3-4 feet from the attic floor. I never really thought about it, but when I stopped and pondered why it was located there, I realized the only plumbing anywhere near that would have to be the basement! (The vent would pass down through a bedroom wall (2nd floor) and staircase wall (1st floor) and line up with the wall next to the closet flange in the basement.) So...I think I found it!

Now I'd like to trace it and confirm that without doing anything destructive. Any ideas? I have a small electric line tracer, I've been considering feeding a wire down the vent and attaching the signal generator to it, then following down the wall with the receiver to see if I can hear the warble. Anyone ever try anything like this?

Thanks again for any help, and thanks for the wet vent comments; I'm familiar with the concept, but couldn't find the vent so it didn't look like an option! However, given that construction would be required to provide a WC privacy, Jamie has hit on my plan; I will be looking to turn the closet into a sink with large counter space for sharpening stones and feed the sink drain into the closet flange. There's not a water line sticking through the wall at this time, but the PEX tubing is just on the other side of the wall, so a tie-in would be fairly easy.


daniel

Lee Schierer
01-02-2017, 1:41 PM
You could have roto rooter come in and scope the drain. They should have a camera with a locator that can tell you where that line goes. You should also be able to see any lines that join in to that line as the camera goes along the line.

Clint Baxter
01-02-2017, 7:00 PM
A wet vent for a toilet has to meet specific requirements, more stringent than those of a normal vent. For instance, it will connect to the drain line using a wye, while a normal vent could use a sanitary tee instead. Typically, if a water closet is plumbed with a wet vent, there will be capped plumbing lines for a sink, and possibly a tub/shower, as well.

Connecting your sink drain directly to the water closet connection could have issues as well. If it is a drain for a water closet, it has to have a trap installed above where you connect to your existing pipe. The trap from your sink must exit horizontally, it cannot just make an "s", and go straight down to connect to the water closet connection. The drain from the sink must connect to a vent line at or before the point where the drain goes vertical.

Incorrectly plumbed drain lines lines can be a safety issue when they allow sewer gases into the home/living space. I'd recommend you at least consult an actual plumber to make sure code requirements are being met, just to be safe.

Good luck with the project, but try to keep it safe for all as well.

Clint

Doug W Swanson
01-02-2017, 10:03 PM
I'm installing a bar sink in our basements family that's about 20 ft from the nearest drain line. Instead of putting the sink closer to the drain line or busting up a bunch of concrete, I decided to buy a pump that mounts to the bottom of the sink. It will pump the drain water up to a 1st floor drain line and save me a whole lot of plumbing. This style pump does not require a vent pipe either. The pump was about $280 on Amazon....

daniel lane
01-03-2017, 9:34 AM
Thanks, guys. Lee, that's a good idea - we used RR for what turned out to be a major shower leak [not a plumbing issue], so I get coupons frequently from them. Next time, I may just call them out to scope everything!

Regarding vent, the plan right now is to tie the sink through the standard 1.5" pipe into the SIDE of the WC drain line, which extends 3 feet above the floor at this time. The top of that pipe would be capped with an air acceptance vent. NC code (917.3) allows this when fixtures are tied to a horizontal branch drain that has a vertical stack (which it looks like it does). Another reason to have RR come scope things, though. Either way, I intend to at least have the design checked out by a licensed plumber before doing anything. But it's looking doable without having to do any demo!


daniel

P.S. For clarity - we called RR about a month after moving in when I noticed water in the light fixture below the master bath. He cleaned out the pipes and I tore open the ceiling, couldn't find a leak nor reproduce the water dripping. Left the ceiling open and eventually noticed it happening again, turns out the grout in the tile seat in the shower had degraded and the seat leaked when water collected on it. So...RR, but not actually a plumbing issue.