I am installing a new kitchen faucet and have this odd copper hard piping coming out from my water supply line. enter image description here

My goal is to remove it and then add this (which comes with the faucet onto the water line, but the right size): enter image description here https://www.homedepot.com/p/BrassCraft-3-8-in-Compression-x-1-2-in-FIP-x-20-in-Braided-Polymer-Faucet-Connector-B1-20A-F/100459572

My question is what is the name of this hard copper pipe? Why would they use this rather than a flex cable (this home was built about 20 years ago if that changes it)? Am I doing something wrong by removing it and trying to replace it with a new cable?

  • 1
    It is called copper water supply tubing that usually came with the older faucet.
    – r13
    Jul 5 '21 at 20:43
  • 2
    If you're in a high rise, there may be fire code rules that prohibit braided connectors. I know this to be the case in Toronto. -- It's got to be copper all the way. Jul 5 '21 at 20:52
  • 2
    You'll have fun trying to fit a new cable..!
    – Tim
    Jul 6 '21 at 7:20

Actually, that's soft copper, not hard copper (which can't be easily bent.) It has a thicker wall than hard copper pipe, and is annealed. Normally supplied in a coil and bent to fit.

"Soft copper line (or pipe, or tubing) with compression fittings" is about as precise a name as you'll get.

It's simple and reliable if installed correctly, but if you don't want to use it or it won't fit your new faucet, you can remove it. If it will fit your new faucet it will probably outlast the polymer one you'd prefer to use.

  • 1
    though depending on how old the copper is it might have hardened over time and you need to re-anneal it if you want to work with it Jul 6 '21 at 7:52

That looks like 3/8" copper tubing and it was a standard way to install the faucets. Many faucets would come with copper tubing and a fitting with a compression sleeve and nut. The shutoff valve would also have a compression sleeve and nut so all that was needed to hook up the faucet was a piece of copper tubing which every plumber carried on his truck. This was the best connection available. Times changed and the copper tubing was replaced with PVC tubing and then came the flexible hose. The faucet designers and manufacturer modified their faucets to accommodate these new, user friendly installation procedures.

You can replace it but I have had to replace some of those hoses because they failed in service and ruptured.

  • 2
    Braided hoses are only good for maybe 5 years (even less if mishandled: twisted or subjected to some cleaning agents). Really, their only advantage is low cost and trivial installation (thus lower installation cost). Copper or stainless tubing is still the way to go if you care about reliability and don't want to replace the hoses regularly.
    – TooTea
    Jul 6 '21 at 6:52
  • 7
    OTOH, I've had braided supply hoses under my bathroom sink and to my toilet for significantly more than 5 years and haven't had a hit of trouble, @TooTea.
    – FreeMan
    Jul 6 '21 at 11:59
  • 3
    @TooTea that seems a little exaggerated to me. Do you have any references for this claim? I would agree that braided hoses would seem likely to fail before a copper pipe, but I have never heard of braided hoses regularly failing in only 5 years. Jul 6 '21 at 13:09
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    @FreeMan Sure, I don't think they are going to fail right after passing the 5 year mark. Most will likely be good for quarter a century, but the risk of the hose bursting definitely increases with its age. It only takes one burst hose to flood half of your house and deal $$$ in damage, so 5 years is IMHO just a very conservative estimate of the potential safe lifespan.
    – TooTea
    Jul 6 '21 at 13:28
  • 1
    @TooTea I'm guessing that 5 years is for legal/insurance CYA. Copper will not handle twisting, mishandling well either an there are many ways they can corrode (see OP's pic.) My experience with a copper supply line for a refrigerator ice-maker tells me it's an inferior choice for that purpose, given that there's no way to move the fridge without putting stress on the line and it's connections and no way to access it without moving the fridge. I've had many braided connections installed well over 10 years without issue.
    – JimmyJames
    Jul 6 '21 at 16:14

That copper tubing is called 1/4" ID soft copper by plumbers and 3/8" OD soft copper by HVAC people. Both identifiers are the same, It just depends on who is using it. It was used by plumbers until those flexible hoses became available. The copper tubing will last a lifetime but the flex will not. In some areas you can only use the soft copper tubing due to the building code that is in force. This soft copper hardens with age and will also harden when worked (bent). I prefer the copper to the flex hoses since it doesn't wear out or break as the flex stuff does. Hope this helps.

  • How does the braided polymer hose wear out if not exposed to light, friction, chemicals other than water, etc?
    – RonJohn
    Jul 6 '21 at 19:17
  • 1
    @RonJohn The inside of the hose is rubber, which can dry out and crack. The metal can also rust (even stainless) due to exposure to water treated with chemicals over time, and wear down in kink/twist spots.
    – TylerH
    Jul 6 '21 at 19:26

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