DIY Home Improvement, Remodeling & Repair Forum > DIY Home Improvement > Plumbing Forum > My THINGY is leaking!

Help Support House Repair Talk by donating using the link above.
Thread Tools Search this Thread
Old 02-21-2010, 02:11 PM  
Junior Member
Join Date: Jun 2007
Posts: 8


I was stunned when I saw your diagram, it's exactly what you'd see if you looked under my sink. The tail piece is white (PVC I think), and everything beyond that is black (ABS I think [I've been reading as you can see]). The black pipe disappears into what looks like a larger diameter black tee running north and south behind the sheet rock. The leaking water is emerging right at the point where the arrow identifies the "inlet." I've read that PVC and ABS have different dimensions and can't be joined except by a special contrivance. My reading further indicates that this connection is called a "slip joint" which is the wrong way to make the connection apparently.

Am I right in believing that either I go to a black tail piece to match the rest of my drain system, or discover how to make my black/white connection correctly? When my father finds out that my wife is using his WWII helmet to collect that dirty leaking water, there will be hell yo pay.

Packy is offline  
Reply With Quote
Old 02-21-2010, 04:36 PM  
Emperor Penguin
Nestor_Kelebay's Avatar
Join Date: Mar 2009
Location: Winnipeg, Manitoba
Posts: 1,844
Liked 2 Times on 2 Posts



I'm not a plumber. Redwood is.

However, there is a standard dimension for kitchen sink and bathroom sink tail pieces. The outside diameter (OD) for kitchen sink tail pieces is 1 1/2 inch while that for bathroom sinks is 1 1/4 inch. So, regardless of what the tailpiece is made of or what colour it is, the trap adapter will be made to fit snugly around a pipe of 1 1/4 or 1 1/2 inch outside diameter. That means the trap adapter should fit around your tail piece snugly no matter what it's made of.

Now, before you take anything apart, use a mirror and a bright light to confirm that the water is leaking out at the top of the trap adapter. It could be leaking out higher up and just running down the back of the tail piece where you don't see it, and accumulating on the top of the trap adapter.

Once you confirm that the leak is at the top of the trap adapter, then the fix is to repair the seal between the trap adapter and the tail piece. There are two ways this seal is made:

1. The threaded cap at the top of the trap adapter may have a lip molded into it's inside diameter that makes the seal, or

2. there won't be any lip on the inside diameter of the threaded cap. Instead, you'll have a bevelled nylon washer under the threaded cap that makes the seal.

If you see a "lip" molded into the inside diameter of the threaded cap, then it's that lip that seals around the tail piece. You can probably fix the leak by cleaning both the OD of the tail piece and putting a new threaded cap on with the same kind of lip on it. Sometimes they sell the threaded caps separately, but if they don't, you'll just have to buy a new trap adapter and just use the new cap to replace your old one. If you can find the name of the manufacturer on the old trap adapter, it'd be best to buy a new trap adapter made by the same manufacturer. That way the caps will be identical. But, more often than not, the cap from one manufacturer's trap adapter will fit on trap adapters made by other manufacturers, so they're somewhat interchangeable in that respect.

If you have a beveled nylon washer under the cap, then it's easier. You can buy a replacement beveled nylon washer at any hardware store or home center. They come in two standard sizes; 1 1/2 inch for kitchen sinks and 1 1/4 for bathroom sinks. Every hardware store and home center will carry both.

So, you need to confirm the source of the leak. Then determine whether it's the cap on your trap adapter that makes the seal or a beveled nylon washer under that cap, and replace the cap or the washer accordingly.

The leak will only occur when the sink is draining, so you'll probably need to get your wife involved in pulling the drain plug on a full sink to confirm the source of the leak.

Redwood may want to add to this if he can see anything I missed.

Last edited by Nestor_Kelebay; 02-21-2010 at 05:23 PM.
Nestor_Kelebay is offline  
Reply With Quote
Old 02-21-2010, 05:01 PM  
Certified Lunatic
Redwood's Avatar
Join Date: Apr 2009
Location: Olde Tyme, Connecticut
Posts: 887

Hi Packy,

The tailpiece does not matter if it is black or, white...
It is tubular which measures 1 1/2" on the OD...
Both Black and White tubular are made of Polypropylene.
Once you get past the slip joints to where the pipe is glued together the pipe is ABS as yours is black. The incompatibility of PVC and ABS is simply that you cannot cement ABS and PVC together. It does not seem to apply in your case.

I would very carefully check to make sure the water you see is not coming down from the basket strainer connection.

If it is the slip joint at the trap you will find the slip joint washer is split and needs to be replaced. If the washer is not split and it leaks worse when you tighten it more, the slip joint adapter is probably cracked and needs to be replaced.

This link may have some useful information for you. How to fix Leaking Sink Drains
Redwood is offline  
Reply With Quote
Old 02-22-2010, 03:54 PM  
Posts: n/a

Originally Posted by Packy View Post
My neighbor, who graduated from high-school, told me that the trouble was that my black pipe shouldn't have been doing business with my white pipe. As far as I know, he isn't prejudiced or anything like that do you think he might have a point?
Unintentional comic Genius. I reread that over and over and just kept laughing. Was he being serious? If he was that's even funnier.
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter DIY Home Repair Forum Replies Last Post
What's that big black pipe thingy in my attic? New2HomeRepair General Home Improvement Discussion 14 11-08-2013 05:58 AM
Leaking pipes JeremyB Plumbing Forum 4 12-17-2011 09:16 AM
leaking in the rain, help! kendallnmatt General Home Improvement Discussion 2 10-26-2011 08:01 AM
Leaking basement Sheila Connell Framing and Foundation 3 11-28-2009 09:57 AM
Leaking Windows SallyBrian Windows and Doors 2 11-06-2009 01:07 AM

Newest Threads