I'm installing a water softener at the house and can't seem to get it
right. Out of the wall is 1 inch copper pipe. I've sweated on a
copper 1 inch threaded male adapter. The soldered joint is good - no
leak :). Then I've wrapped teflon tape clockwise onto the copper
threads and attached a 1 inch female threaded PVC adapter to transition
to PVC for the rest of the job. Now I have a leak!! :( about 1 drop
per minute at the threaded joint. I've retaped and tried several times
to stop the leak, but no luck.
I did the same thing for the 'outlet' and have no leak... Am I doing
something wrong? Is there a better way to go from copper to PVC?
Could the PVC adapter be damaged? (it looks OK on visual inspection)
Any suggestions and recommendations are welcomed!
Never use a female adapter on the PVC side. Reverse everything
so that the PVC terminates in a male adapter.
You *may* get the present arrangement to stop leaking but,
over time, the female adapter will fail due to the outward
forces of the tapered threads.
Don't forget to add a bonding jumper around the plastic
Correct on both points. Plastic to metal connections should always be
male plastic to female metal. I learned that the hard way after laying
a new hydrant line. Middle of winter with a couple feet of snew got a
massive leak. Fortunately I was able to bypass that line. When dug up
in the spring I found that I had done the female plastic to iron error
and it had split on the parting line. Just screwing them together puts
a big strain trying to force the female fitting apart.
I'll second or third the recommendation NOT to use female plastic threaded
adapters. The few times I've used them, the metal fitting ALWAYS cracks the
plastic fitting at the seam. They shouldn't be allowed to sell those
If you're going to use threaded adapters, use a female copper adapter, and
a male PVC adapter.
However, the best way to join copper and PVC is with a specialized fitting
made for the purpose. One side is a PVC fitting that you glue to your PVC
pipe. The other side is a copper fitting which you sweat to your copper
pipe. The two halves are joined with a rubber gasket and a threaded
coupling to tighten them together. The gasket allows the PVC to expand and
contract with temperature changes without causing a leak. They're expensive
(about $3 to $5 per fitting), but they work great.
Thanks for the information. Do you know of any links to pictures of
the specialized fitting? I'd like to see what one looks like before I
go to the store - to make sure I get the right thing.
Should I be able to get this at Lowes or Home Depot or will I need to
find a plumber specialty store?
Another concern I have is theres only about 2 inches of copper pipe
left coming out of the wall. Once I make another cut I wont have much
left to work with.
Skeez is right here but I'm going to assume you've never done this like
I didn't until recently, if you have I'm wasting your time.
After you sweat the old coupling off use the wire brush gently around
the fitting. After it cools then use the plumbers sandpaper on it so
the new fitting will go on easier. You won't sand it back down to the
copper. I would use just a little more flux than normal when you put
the new coupling back on. When the flux quits bubbling or you see some
of the old solder melt then stick the solder to the joint. Two more
important things to do--make sure there is no water in the pipes and
don't move the soldered area until it cools completely on it's own.
Hope this helps--wish I had this advice to start off !
They're called "Transition Unions". The only example I could find is at:
That's all one line, so watch the word wrapping...
I bought ours at Lowes, but I've also seen them at Home Depot, and our
local hardware store. They're usually in the same area as all the other
CPVC fittings. Some have metal rings joining the two halves, others have
plastic rings joining the two halves. Either would work, but I prefer the
All the ones I bought are for CPVC, not PVC. If you're plumbing supply
lines for your water, you should use CPVC anyway.
The fittings come in a variety of configurations. I used two types:
1. A brass drop ear elbow with the gasket and CPVC fitting on the bottom.
I used these for all of our shower heads, and everywhere I was going to
install a shut off valve.
2. A straight "union". Female brass threads on one side, CPVC fitting on
the other. I used these at our hot water heater, and anywhere I installed
a water hammer arrester.
1. Leave your current copper male fitting in place, and get one of the
transition unions that have a brass female thread. Then just thread on
the new fitting with teflon tape.
2. Heat the fitting with a torch as others have suggested and pull it off
instead of cutting the pipe. Clean up the end before sweating on the new
One note... Be sure to slip the joining ring over the correct end of the
pipe, and facing the right direction, before gluing or sweating the
fittings. I forgot to do that once or twice and had to cut out the lines
and redo them, with another $5 fitting. :)
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