I am installing a new kitchen faucet and need to rotate the shutoff valve 90 degrees. The shutoff valve is connected to a copper pipe with a compression fitting. Can I simply loosen the compression fitting nut, rotate the valve and then retighten the nut. Nothing is 100% but will I likely or not likely to have a leak after tightening.

  • 1
    How much do you "need" to do this? It is essential because of interference or length of connecting hose or would you like to do this to make a neater installation? Mar 22 at 0:41

3 Answers 3


Yes. While you will find some folks here who claim compression fittings are "use once" that does not match my experience over multiple decades. Perhaps because I don't overtighten them the first time...

Quotes from a manufacturer document: https://www.beswick.com/resources/the-basics-of-compression-fittings/

Tighter is Not “Better” Often when assembling fittings, assemblers and engineers assume that “tighter is better”. This does not hold true for compression fittings. As described in the “Ferrules” section above, the optimal seal is created by a line contact between the ferrule and the tubing. Insufficient tightening of the compression nut will not deform the ferrule enough to create this contact, but over-tightening will deform the ferrule too much, creating a surface contact. A surface contact weakens the seal and often results in leaks

Disassembly and Re-Assembly The ease of assembly and disassembly is one of the reasons why compression fittings are so widely used. Disassembly involves simply loosening the compression nut or screw. Re-assembly can be accomplished in a similar manner to the initial assembly, although typically fewer turns of the nut are required, since the ferrule is already swaged to the tubing. It is important to note however, that compression fittings can only be disassembled and reassembled a few times before either the ferrules and/or the fitting body should be replaced, to ensure a leak-tight seal.

Do be sure to hold the fitting or valve while loosening the nut. It's quite easy to twist a pipe or tube if you just use one wrench on the nut. You need a second wrench holding the other part so the pipe is not taking the force.


Compression Sleeves Ferrules

are considered tricky if you try to reuse. It might work or it might not work.

The reason is clear, the ferrule was deformed to create a seal. Now you are trying to deform it again while still have a seal.

Usually one tries to screw it more to create the seal. You can always try that first before having to go true the process of removing it.


I've bought a house built in the 90's. I've been replacing all the multi-turn valves with quarter turn valves. I had a couple that the packing was leaking. Using this tool or one like it it's really easy to remove the old compression fitting. If it was my project I would probably replace the fitting, if not the whole valve if they aren't quarter turn.


  • This is effectively a link-only answer, or perhaps a comment.
    – Ecnerwal
    Mar 23 at 15:33

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