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Plumbing in the Home/Copper waste drain pipe leak.


I have all copper supply and waste piping in my house, all in good condition with no noticeable corrosion.  Today I noticed a very small leak at a joint in the main 3-inch copper waste line in my basement.  It appears to be a new leak as there are no water marks on the pipe or the floor.  My question is can I heat up the fitting and try to resolder the joint while it's still attached?  I'm somewhat leary about heating up a pipe with possible sewage gases in the line (since there are no traps between this point and where it runs to the outside).  If it's unwise to do this, is there another option that would work on copper, like caulking or liquid nail, etc.?  Thank you for your time.

Hi Jason,
Sorry I did not answer before now.
That could be problematic unless you have experience sweating copper and even then it is a bit different when dealing with the larger sizes and with the age of the system. In California I doubt there has been but very limited use of Copper DWV systems in the preceding fifty year. I see you are in Pennsylvania and I would guess the same applies there.

You can stop the leak in several ways like you suggest with glues/caulk but I would recommend wrapping a rubber tube like material (tire tube would work or a rubber sheet from the hardware) and using stainless steel hose type clamps and securing it in that fashion.

Now if you want to try to solder (sweat is the plumbing term) the leak you need to visualize what you are trying to do and what has happened if you can. The annulus that the solder bonds in (space between the socket of the fitting and the pipe) is fairly deep (from 2 – 3 inches) and it is likely very corroded and will resist bonding. There is, on the market, self-cleaning fluxes that you would have better success using to make such a repair and it may work easily if you can control the heat properly. You would want some 50-50 solder (I prefer the sticks on large sizes but the coiled will work also).

Unless you know about sweating copper I would not recommend you trying as this is a difficult learning process (that is trying to repair an old large size leaking joint) and there are several things you need to be aware of. If it is easily accessible and you decide to try to add solder be sure to clean really good around the outside of the joint and have the self-cleaning flux liberally spread so that the heating of the socket will draw it into the annulus and when the pipe is hot enough to melt the solder it should draw into the annulus. It is tricky in that you have to preheat the pipe and then heat the socket a couple of inches back from the entry point as the hotter area will draw the solder in…

Jason if you do not know what I am talking about then do not attempt the soldering job and just patch it. This is really a job for a plumber that is used to working with copper and unfortunately not all plumbers today are used to working with copper…

Good Luck  

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Cortez (cort) Cate


PLEASE read this entire introduction. I have been doing this for a long time and I have come to the conclusion that if you are not willing to take the time to write a detailed question then don't expect a detailed solution! I am getting far to many questions that do not give enough detail to warrant a good solution. I realize it is a little difficult to formulate a good question but if you want a good answer you have to give me good this entire introduction please....remember this website is world wide I have no clue where you live if you don't tell give more detail on the fixture you are having problems with...a one piece eljer 3.5 gallon flush will be totally different than a one-gallon flush toto.....details are important. I can answer most questions related to residential and commercial plumbing for many buildings. I have sufficient knowledge of the UPC and UMC. I will speculate for you if necessary. In those cases I will try to give you some guidance and you should use that to refine the question further and we, together, can seek the answer via a follow up. Plumbing codes and practices vary around the world--If you don't tell me where you live the answer I give may not fit your locality. I am giving my time to you as a way of fulfilling my perceived obligation to share. I am here to try to help you find a solution to your problem. REMEMBER, If you want a good answer you need to ask a detailed question and include where you live, type of pipes, type of building, water pressure if it is a water problem, type of heater, age of appliance & building all these and many more are variables that have an effect on various situations. Detailed information will help produce a better answer.


Since 1972 a California licensed B-1 General Building Contractor, C-36 Plumbing and C-16 Fire Sprinkler Contractor; also installing and servicing Heating, Air Conditioning and Sheet Metal operating as C and C Building and Plumbing, California State License 279516. In 1995 I downsized the company to become semi-retired. Still I remain active in the construction industry. As head of a company I placed personnel and job safety as the number one objective followed closely by training and continuing education. Always seeking to stay informed of leading edge technology in the industry. Also I have spent several years as an Apprenticeship Instructor in the Pipe Trades Unions. Additionally I am a certified OSHA instructor.

United Association of Plumbers and Steamfitters Instruction Training, Ann Arbor, MI Bakersfield College, Bakersfield CA Cal Poly San Luis Obispo, San Luis Obispo, CA Foothill College, Los Altos, CA California Licensed Contractor from 1971

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