I have an older house with lots of pinhole leaks in the copper pipes. From what I have been told, you have to replace the pipes, copper or PEX or maybe something else. I am trying to avoid the ~$10k to do this, not that it is not worth that or that people shouldn't be paid, but it is a lot for me.

Can I replace the copper a little bit at time, maybe one bathroom, a kitchen and a hammer arrestor to stuff, etc.? Do I have to go in full throttle with manifold and do it all at once? I'm concerned on some of it because copper comes out of the water tank, and I don't know if I can mix things up down the line, or if I have to start at the tank with PEX, then I have the Pressure/expansion tank.

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    My plumber replaced poly-B in sections, one bathroom at a time etc... Wasn't an issue. Some sections ended PEX, others started PEX.
    – P2000
    Commented Feb 25, 2021 at 20:48
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    All plumbing can be done in pieces/sections, it just takes longer to finish. Would map out section want done and make sure you have everything to finish that section. Quite a bit of cost would be labour and if comfortable, can do most plumbing replacement work yourself. There are quite a few push to connect fittings now and usually can get by without any soldering.
    – crip659
    Commented Feb 25, 2021 at 21:23
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    Can use copper and/or PEX and can even mix them if you want. Fittings available to go copper to PEX and the other way.
    – crip659
    Commented Feb 25, 2021 at 21:40

1 Answer 1


You can do it a bit at a time.

Of course, any bits that are leaking that you don't replace will continue to leak until you replace them.

You can (or could when I was shopping, it was some years back) beat the price of a manifold with a handful of Tees and Valves. Pex does not require the use of a manifold, though the idea of using individual home runs of relatively inexpensive tubing rather than branch lines splitting up to feed various fixtures may still have merit.

Where possible, try to treat PEX as PEX, not as rigid pipe. For very tight bends where you have no other way, you might need an elbow. Anywhere you have space, just bend the tube - it's cheaper and it flows better and it's one less spot to leak. Know and respect the minimum bend radius of the tubing you use (look up the manufacturer's specifications.)

In my local area, the piping within 3 (linear pipe) feet of the water heater has to be metallic (one of the changes they make to the IPC code which they base the local code off of.) You may not have that or a similar requirement - if you do, and if your water is eating copper, you might want to use stainless steel, which seems to be easy and affordable on the internet but gets the blank stare response at the hardware store. I would not suggest using galvanized iron pipe, based on every galvanized iron water pipe I have ever disassembled.

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