Is there any way to run a brand new 3" water line pipe through the inside of an existing 6" water line pipe. I want to make sure that the 3" pipe is not rattling around inside the 6" pipe. Any way to keep it in a fixed position as well?

  • 2
    what distance are we talking about?
    – JACK
    Oct 9 '19 at 16:17
  • 1
    Hello, and welcome to Home Improvement. Why do you want to do this? And, you should probably take our tour so you'll know how best to participate here. Oct 9 '19 at 17:07
  • 1
    must the 6" pipe remain open?
    – Jasen
    Oct 10 '19 at 2:58

There are products called "pipe casing spacers" which can be used for such a purpose. I'm not meaning to endorse this particular brand but this is an example of such a device:

Pipe Casing Spacer

A drawback, however, is that the original line will be significantly blocked by the combination of the new pipe plus the spacers, so if you need to maintain flow in it, what you get will be quite a bit less than what you currently have.

  • That's cool, but looks very expensive and specialized. OP is going to have to really need the pipe centered to use something as well built as those.
    – JPhi1618
    Oct 10 '19 at 15:38

If the only reason to do this is to prevent "rattling" of the smaller pipe inside, meaning you are NOT going to use the 6" pipe for anything else, then you can just fill the annular space with expanding foam. It would not be important that it is suspended evenly in the larger pipe, it would only matter than it can't move in there.


Depending on your very vaguely specified needs, there are plastic products made to keep well water lines (typically 1 or 1.25 inch) (roughly) centered in the bore of a drilled well, fairly inexpensively.

Few are sized for a 3 inch pipe, though.

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