Hot Topics: Basement Sink Drain Leak Repair

A sink in a basement with a pipe leading to a drain in the floor.

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Original Post: Need advice for fixing basement sink drain

SamAlex Member

Hi all—I am looking for advice to fix the drain coming off my basement sink. It has been set up like this since I moved in, but regularly leaks onto the floor. It looks like they tried to set up drain pipes that lead the water over to the drain in the floor. (See pictures—although you can't see the floor drain in the picture, it's just to the right of where the drain pipes end.)

My guess is there is no point in trying to "repair" this and I should just replace all the pipes/parts under the sink. I am a novice at plumbing, so I am not even sure what all the pieces and parts are I should buy at the hardware store. I also assume I need to clean right under the drain before attaching any new pieces since it looks so corroded (see second picture). If so, what do I use to clean it? Any help or advice you can provide would be greatly appreciated.

The concrete sink in the basement.

The underside of the concrete sink with a rusted pipe connection.

Zorfdt Forum Topic Moderator

We'll give that setup points for creativity!

What is your goal with it? Your simplest solution might just be to replace the old lead pipe with PVC and use a rubber Fernco coupling to make the connection to the sink, and let it just keep draining into the floor drain. It's probably not the best solution, but certainly the easiest.

The best way would be to cut up some of the concrete and tie into a main drain and do it all properly, but that may be more work than you're looking to get into.

Do you know if the floor drain drains into the sanitary system, since some floor drains just go outside or into a separate storm water drain? This may change the solution, as well.
SamAlex Member

I got the drain taken apart today. I went to the local hardware store and was told they no longer carry the funnel flange I need to connect the pipes to the bottom of the sink. I was advised to call a local specialty plumbing store, but they do not carry the part either. I don't think I can use the rubber Fernco coupling to make a connection—it wouldn't fit.

Any ideas what I can do to get this operational? I am currently soaking the flange piece in PB Blaster in hopes I can remove the nuts/bolt. IF I can salvage the piece, do I need some kind of a ring on it like you install with a toilet?

To answer your question, I'm fine with it just draining into the floor. That drain goes outside and the sink is really only used to catch water from the washer, so I don't want to spend the time and effort to break the concrete and tie it in properly.

Norm201 Member

Try another plumbing house, but I think you will find the part is no longer available. You might consider getting a new stationary tub/sink. They're not all that expensive. Your big problem is removing the concrete sink you currently have.

Another makeshift idea would be to knock out the drain from the sink completely. Then buy a new drain assembly and using hydraulic cement, install it.

Zorfdt Forum Topic Moderator

I've never seen a connector like that. I think even if you get it working again, it looks like it's meant to be used with lead pipe that would flare at the top. Lead piping was a bit before my time (and likely before a lot of people's, here). I'm not sure of a better answer than what Norm provided.

SamAlex Member

I was able to cut the old bolts off the original cast iron piece they no longer produce. I bought new bolts/nuts and used the existing cast iron and lead pipe flare pieces to secure to the adapter under the sink again. I tied the original lead pipe flare piece into the new PVC and secured the connection using the rubber Fernco coupling. Lastly, I put an elbow on at the very end so it won't move around and goes directly into the floor drain. It seems to be good now; there is no more leaking. Thanks for everyone's tips and advice!

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