# coupling PEX underground?



## wombosi (Apr 22, 2008)

I need to couple together some 3/4" pex underground, before coming up into my mechanical room. It's the main water supply line.

I've never plumbed with PEX before and have no PEX tools. I assume the "sharkbite" fittings are not appropriate for underground use?

Do I need to buy some special PEX tools to be able to properly deal with fittings?
I don't anticipate doing much more with PEX, and once I'm in the mechanical room it will all be copper (already is).

Thanks.


----------



## rjniles (Feb 5, 2007)

I would try to get longer lengths of pipe to eliminate any underground couplings. If you must, here is about the cheapest crimp tool you will find:

http://www.lowes.com/pd_324341-943-...storeId=10151&ddkey=http:LowesIframeTransport

It is used with a pair of vise grips to provide the crimping power. Good for low volume jobs or very tight spaces. I used a pair to replumb my camper.


----------



## moopey (Sep 14, 2010)

i agree with previous post. Try to obtain longer run of pex to avoid any fittings. Even when using copper, plumbers use soft rolled no joint copper to avoid fittings.


----------



## LateralConcepts (Jun 6, 2010)

schmolze said:


> I need to couple together some 3/4" pex underground, before coming up into my mechanical room. It's the main water supply line.
> 
> I've never plumbed with PEX before and have no PEX tools. I assume the "sharkbite" fittings are not appropriate for underground use?
> 
> ...


I wouldn't use PEX underground. Use 200psi Poly. You can buy it in a 100' roll. Make the transition to copper or PEX by using a brass 3/4" barbed by thread (MIP) adapter. Then an FIP adapter.


----------



## wombosi (Apr 22, 2008)

guys, thanks for the advice.
unfortunately, i already have a 100' roll of PEX buried 4' down, running from house to barn. no way to redo this at this point.

options are:

1) splice underground and continue the trench, to come up vertically into the mechanical room. the vertical part will require some sort of "heat tape" as it will be in unheated space.

2) come up into the unheated space right where i am now wiht the end of the PEX sticking up a few feet, and run it along my drainage chase and into the mechanical room. this way at least the joint will be in the open, but i'll have much more of it (maybe 20') exposed to unheated space and requiring some sort of heat tape.

thanks. hope having hte PEX underground is not irreparable in terms of being able to get water through it. i did this over a year ago and people told me it was fine for this application. granted, i should have bought a longer roll of it back then. didn't realize joints were such an issue.


----------



## plumber666 (Oct 7, 2010)

I'd use a "Mueller" corporation coupling, not a crimp coupling. It's like a compression fitting, but different.


----------



## burnt03 (Sep 20, 2009)

Here's what plumber666 is talking about (H15403)

http://www.muellercompany.com/water/products/default.aspx?catid=6

Nothing wrong with laying PEX in the ground, they use it here all the time with the noted compression couplings and I've never seen a problem with it. 

Make sure you use a stainless steel insert/stiffener


----------



## COLDIRON (Mar 15, 2009)

I'd be afraid of splicing anything underground without knowing where it is and how deep it is. If I had your problem I would probably dig a deep hole and install a sonotube or a box where the splice is so I could look in and check it once in a while or if there is a leak somewhere that would be the first place I would look.


----------

