I know that copper is naturally antibacterial, and that seems like an advantage of running copper pipe.

If PEX is becoming more common, how are problems with bacterial growth inside the pipes being avoided, or is this just a non-issue altogether since things like water mains and wells aren't copper anyway and people are just bringing up bacteria as nothing more than an irrelevant apologetic for copper pipes?

  • The antibacterial properties of copper are greatly oversold by the propaganda you've evidently been exposed to. One it's been in place a few months the interior of the pipe is not longer of any use for that purpose, unless you're wire-brushing the inside of the pipe regularly...
    – Ecnerwal
    Jul 21, 2023 at 19:27
  • I mean is it propaganda? That's more or less exactly what I am asking with the wording "... nothing more than an irrelevant apologetic for copper ..." in my question. Jul 21, 2023 at 20:02
  • Where are you getting your water? Municipal water supplies often contain an antibacterial agent added at the pumping station; It burns off, but since there's no way for bacteria to get back in....
    – keshlam
    Jul 21, 2023 at 20:33
  • Stagnant/unused water in pipes is the biggest problem. You go away for few months and the water in your pipes will need treatment and use. Use two buckets filled with water. One is just left alone for two weeks. The other has the water changed everyday, I think you will tell which one is which.
    – crip659
    Jul 21, 2023 at 21:03
  • In my case, it is a well, so I would expect there to be some bacteria in the water supply. Bad, good, moot? I don't know. Jul 21, 2023 at 21:05

1 Answer 1


Yes, it's propaganda.

Have an authoritative site: https://copperalloystewardship.com

Relevant quote, emphasis added by me:

Laboratory testing shows that, when cleaned regularly, antimicrobial copper surfaces kill greater than 99.9% of the following bacteria within 2 hours of exposure:

You're not cleaning the inside of your copper pipes, unless you're as paranoid as Howard Hughes in his dotage, and equipped with a budget of his scale as well.

  • I appreciate the confirmation. I thought it sounded like one of those anti-technology type of arguments, but wanted to see if there was any truth to it. Looks like not. Jul 21, 2023 at 22:11

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