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Buried Service Line

413 Views 6 Replies 4 Participants Last post by  TheEplumber
Purchased a new house in December, should be moving in about 2 weeks. Noticed a few signs that I may have a water leak in yard. Dug up the spot today, found the leak. Black plastic pipe (polyethylene I assume) coming from meter, meter is at sidewalk. Copper pipe entering home through foundation. Leak is where the 2 pipes are joined together. Both pipes are 7/8in O.D. A compression coupling was used and is leaking on the plastic side. I believe this was the original install and not a repair, seems to have been leaking for years.

I've had the water off for over a month now. Been doing a lot of work in the house but don't live there yet. House was built in 2006, located near St. Louis Missouri (Lake St. Louis).

My question is about the proper materials to fix this. I found another compression fitting of the same style (JMF 7/8 Compression Fitting) and says it can be used on copper and plastic, but the plastic pipe requires a brass insert to keep from crushing the pipe. I have not yet taken apart the leaking one to see if it has an insert in good shape to reuse, may check tomorrow after work. Is there a better fitting to use? Where do these larger inserts come from? I have no problem finding smaller ones. Is there another piece of material not made for this that is an acceptable substitute? Any other advice?

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Thanks for the quick reply. I’ve had the water shutoff at the meter for several weeks so I wouldn’t have to work in more mess than necessary. I didn’t check to see if the coupling was tight yet. The plastic line looks like it is not inline with the coupler, has an angle to it, so I thought maybe it was just poorly done the first time. I’ve got a couple plumbing stores local to me that I will check with tomorrow.
Rommel, welcome to DIY Chatroom!
If I followed your post, you are looking for one of these
There are 2 brands I'm familiar with- Ford and McDonald- One is equal to the other.
These are also known as Pak Joints in my area. I buy them from a wholesale plumbing store.
The 7/8 OD is the OD of 3/4" Copper tube. Poly pipe comes in iron pipe OD as well as copper tube (CTS) You have CTS poly. The stiffener is a stainless steel insert and is required on the poly end only. Yours, if it is there should be in good shape. You must request a stiffener when purchasing the coupler- it is optional.
3 possible reasons why you have a leak-
Outside of poly pipe scratched
missing poly stiffener and poly is out of round
Bad stiffener
Coupling compression nuts loose.
I would shut the meter off and try tightening the nuts. Then turn water back on and check for leaks.
I would also call the water dept and see if they would help or source the repair parts.
Looks like when the ground settled, the pipes pulled apart. There was well over an inch of space between the pipes when I took the old coupling off. The pipes were damaged from being pulled apart. I have to cut them both back a few inches and put a piece of copper in. There was a stiffener in there, looks to be in good shape still.

I picked up a pair of McDonald 3/4 pack joints/couplings with the split clamp ends. I want to make sure I don't over tighten anything. What is the rule on tightening the coupling nuts to copper and the plastic. Hand tight plus quarter or half turn? More or less? Rule for tightening the split clamp? Snug? Snug plus more? I did get a new stiffener too, figured it wouldn't hurt.

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