I have a sink with two pipes connecting to the tap (a.k.a faucet) - one for hot and one for cold. There is no hot water in the house, so the hot pipe is disconnected. That means if you open the tap halfway between the hot and cold, the water just flows out of the disconnected pipe instead of the tap. My first thought was to just plug the end of this disconnected pipe, however I fear that this will result in water standing in the pipe leading to legionnaire's disease type problems.

This seems like a pretty common problem that probably has a standard solution, anyone know what that is?

  • Where is this house located? Is the hot water distribution system drained of water? How are the bathroom lavatories and shower plumbed? I lived for two years in Fiji with only cold running water and so I know how to do it in a tropical climate, but I am curious how you are managing this. Commented Nov 16, 2017 at 15:47
  • Yea this is in the Caribbean, there is no hot water distribution just a tank on a hill with a single pipe running down to kitchen sink & bathroom sink.
    – Brendan
    Commented Nov 17, 2017 at 14:13
  • For the record I think I had gone a bit troppo when I wrote this - the water from that tap is obviously not safe to drink in any case!
    – Brendan
    Commented Aug 19, 2019 at 8:05

1 Answer 1


Three ideas off the top of my head:

  1. Terminate the end of the disconnected pipe with a valve. You can mitigate legionnaire's risk with a maintenance plan to open the valve in order flush the disconnected pipe every month or so. (More research needed on required frequency of flush through if you do choose this option). I'm against this option because of the maintenance: it's ongoing effort, you may forget it and not do it as frequently as required, if/when you sell this house it's almost certain that you'd forget to tell the next owner and/or they wouldn't take the maintenance requirement seriously.

  2. Branch the cold pipe, and feed one branch into the cold inlet pipe and one into the hot inlet pipe.

  3. Buy a replacement tap which only expects feed from one pipe. This may be problematic, as I think most non-mixer taps are designed for smaller mounting holes than mixer taps are.

Option 2 seems to be the winner as the others don't seem overly practical.

  • Happy to convert into three separate answers if wanted. I know on other stacks multiple answers in one box are frowned upon as people may want to vote up one option and vote down another.
    – AndyT
    Commented Nov 16, 2017 at 12:42
  • Options are fine. Legionaires is a concern and I'd disregard #1. #2 is the ticket, both for sanitation and flow.
    – isherwood
    Commented Nov 16, 2017 at 12:48
  • @Isherwood - Thanks. Revised answer, which now only has one recommendation anyway.
    – AndyT
    Commented Nov 16, 2017 at 12:57
  • Thanks, I think option 2 sounds best. Currently using option 1 but absolutely agree it is dangerous - we will forget to clear the pipe.
    – Brendan
    Commented Nov 17, 2017 at 14:15

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