Plumbing in the Home/Drain Pipe



Under our bathroom sink is a drain pipe that just pushes into another pipe(the one coming out of the ground), and is not sealed or really attached in any way. It has been that way for years. I kind of like this because if the drain gets badly clogged, it is easy to pull out the pipe and clean. I have not noticed any leaks, but this can't be a good idea though. I do have pvc cement if I need it, but do I have any other options?


Depending on the pipe size, there are several solutions. Typically,a bathroom sink is one and a quarter inch outside diameter. The connection between the pipe coming out of the trap, called a "trap arm" and the actual drainpipe is usually made with a fitting called a trap adapter. This is also called a "slip joint" fitting.

Probably the easiest thing to do would be to find a rubber coupling adapter that would fit on both pipes that can be secured in place by built in hose clamps. These are fairly commonly available at a big-box store or a plumbing supply.

You actually do not want to make this a permanent joint since it occasionally needs to be disassembled for maintenance access like snaking the line.

Good Lock,

---------- FOLLOW-UP ----------


I mentioned a pipe fits into another, but it is actually a pipe pushing into an elbow that connects to the outside drain. The pipe that goes to the elbow has sch 40 on it, and the elbow looks like it has 1-1/2 on it. With the way it is set up, I don't think I could fit a rubber coupling on it.

This part:
 goes into this elbow:, which is    
 flush with the outside wall.

Here is what pretty much the whole thing looks like, with the exception of the pic with the dark brown wood in the back. That is another sink, and I like how it is setup as it screws apart.

Thanks for the pics, they help.

Yikes! This looks like a totally bootleg set-up, none of it meets code or good plumbing practice.  In the 4 picture group, I don't even see a P-Trap included nor does the system appear to be vented. I'm surprised it even drains properly.  Do you get sewer smells in this bathroom?  The reason drains have p-traps is to prevent sewer gas from coming back into the house. It looks like the other sink has a trap at least.

With the setup you have, I would add and extension piece to the outside elbow so that it sticks out of the wall on the inside. Add a trap adapter or some kind of a slip joint or something at the connection inside so that it can be taken apart for maintenance.  Still bootleg but if it has been working...  Whatever! LOL

Good Luck,

---------- FOLLOW-UP ----------


It did have a p-trap, but I think the venting is done on the same pipe that the toilet uses. I do not see venting for the second bathroom for the toilet or sink. Outside the ventless bathroom, there is a slight seperation of sewer pipes, but I better keep my questions on one situation at a time.

I put some new pipe on the outside elbow so that it extends into the house. There is actually no room to put the original piping back on because there was a snug fit from the outside elbow to an inside elbow. Since the setup was all cemented together I will have to start over.

I think the reason the original pipe looked odd was because the place for the outside drain sits so low:

What do I need to get for a drain pipe besides a p-trap and some 1-1/2 pvc? The other bathroom is using 1-1/2 pipe but then it narrows to a smaller pipe: I like this setup if it's up to code, but I already bought the rubber coupling so I might has well just use it for connecting the 1-1/2 pipes.

The whole gallery is here: A few pictures show a slip joint nut that has almost completely corroded into. I have no idea how that is happening.

Thanks for the help.

sink trap assy.
sink trap assy.  
Hi KC,
Okay, I would chuck out all the old pipes and start fresh. The pipe coming out of the bottom of the sink's pop-up drain is called a tail piece and usually 1-1/4".  I would get a new 1-1/4" p-trap "kit" called a "trombone trap".  It will attach at the tail piece with a slip joint feeding into the trap. You may also need an 1-1/4" "slip joint extension tail piece" if the trap is low.  The outlet end of the trap slides inside the 1-1/2" pvc from the wall (hence the "trombone" name) and is connected with an 1-1/4 X 1-1/2 trap adapter. This is the correct way to do it.  You can also use a properly sized rubber coupling in place of the trap end adapter.
Good Luck,

Plumbing in the Home

All Answers

Answers by Expert:

Ask Experts


Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


Retired, Licensed General Contractor with Plumbing license. Active Home Inspector, Litigation Consultant and Infrared Thermographer, Online Marketing specialist.

Publications "Rain Maker" as "Inspector Dana", about making money online.

30+ years in the building trades, Licensed General Contractor (Retired), Certified Infrared Thermographer Internet Entrepreneur, Amazon & eBay Merchant (deals-by-dana)

Awards and Honors
Listed FHA Fee Inspector, FHA 203(k)Consultant, HUD Mobile Home Inspector

Past/Present Clients
Home buyers, sellers and owners, Investors, Commercial roofing companies (infrared roof scans for moisture intrusion, Litigation Consulting for "Slumlord" laws in SoCal

©2016 All rights reserved.