My backyard has existing copper pipes outside that I want to reroute. To keep like with like, I'll just continue using copper. Are there any considerations or special types that I need to be aware of? Specifically, is there a special type of pipe that is better suited for outside conditions.

No snow or freezing temps here.

  • The question is too broad, but do consider switching to pex. It's really nice to work with and more durable (in terms of corrosion).
    – isherwood
    Feb 17, 2020 at 16:29
  • 1
    I'll edit my question and may still be too broad. I'm asking if I can use any copper pipe, or I need a special "outdoor rated" type
    – dabi
    Feb 17, 2020 at 18:36
  • @isherwood: is it more durable with respect to termites/ants/moles? I've never heard of Cu pipe corroding...???
    – peinal
    Feb 21, 2020 at 2:20

2 Answers 2


If this is outdoors and possibly underground, understand that there are two types of hard copper pipe (as opposed to soft tubing); type L and type M. Both have the same external diameter so they both use the same fittings, but type M has thinner walls. It is for use where the pipe is going to be somewhat protected, as inside of a stud wall in a building. Type L has thicker walls so the inside diameter is slightly smaller, but it is much more resistant to accidental puncture and will last longer in terms of corrosion when in direct contact with soil. Some jurisdictions require that you use type L outdoors, so it's just better to go that way.

  • A few years ago I ran a water line from my house to an outbuilding and I asked a similar question. The opinions varied whether to use Type L or M and whether to solder or braise. (By "vary", "Just solder type M and you'll be fine!" to "Only use L and only braise or else!") I wound up using L and braised.
    – Duston
    Feb 21, 2020 at 14:53

For copper: A quality torch helps to solder. Propane works, but I like MAPP gas--it's better with non-lead solders.

Pipe is rigid and goes by inside diameter. Tubing is soft can be bent and goes by outside diameter. 1/2” pipe and tubing will not fit together without adapters.

Make sure to use non lead solder and flux that is made for potable water.

Last, prior to soldering clean the outside of the pipe inside of the couplers , or fittings with a fine sandpaper or plumbers abrasive cloth to remove the varnish.

A tip: if your pipe has water in it the water will vaporize and cause leaks. Take some white bread remove the crust and stuff the bread in the side that had water. Once fully assembled remove any aerators and flow water to remove the bread.

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    "Pipe" of a size (such as 2 in.) all has the same OD regardless of wall thickness , whether thin (Sch 20) or thick ( Sch 80). So all "2 in." pipe will thread together. And "2 in" is not the OD of the pipe , it is a name . Regarding NPS in the US. Tubing is anything that is not made to NPS pipe dimension , regardless of strength or shape ,such as square. Feb 17, 2020 at 17:02
  • @ blacksmith you did not read what I wrote! I specified the difference in tubing and pipe because 1” tubing that is easy to bend will not connect to 1” pipe or 1/2” as the op asked I have been called several times over the years when a DIY person got tubing because it is easy to bend and could not connect the 2 together. The op asked for things to be aware of and this is the reason I mentioned it did you not know this?
    – Ed Beal
    Feb 17, 2020 at 18:40
  • "Tubing" is a description of sizes, not strength, ductility or material ( per ASTM). I realize in the plumbing trade , copper tubing is usually a relatively soft, ductile material , but I am referring to the general case. ASTM has two separate committees to write "tubing" and "pipe" specifications , although mostly the same people are on both committees. Oil well tubing is a completely different story but the general public almost never sees it. Feb 18, 2020 at 16:34

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