Please forgive me if I get any terminology wrong here, I know nothing about plumbing…

We have suddenly stopped getting cold water in our downstairs bathroom and cistern. No issues with hot water anywhere.

We tried holding our hand over the tap and various things to try and fix an air trap (if that’s what it is). At one point when we did this, we held our hand over the tap and ran the hot water, then the cistern filled with hot water, but still no cold water running from the tap or filling the cistern.

We have checked and all of the valves seem to be open and cold water is coming through fine in the kitchen.

Any help would be appreciated!

  • 1
    Usually when water stops there is one of two reasons. Someone has turned off a valve, easy fix, or there is a blockage in the line. Hot water line is usually more often found to have a blockage from sediment, but can happen in cold water also. Water pipes sometimes not as clean as we hope they are.
    – crip659
    Commented Dec 20, 2022 at 19:27
  • Do you have freezing temperatures outside
    – Traveler
    Commented Dec 20, 2022 at 19:41
  • No, definitely not cold enough for frozen pipes
    – K Mac
    Commented Dec 20, 2022 at 19:47
  • OK, so it is not that, do you get cold water anywhere else in the house
    – Traveler
    Commented Dec 20, 2022 at 19:52
  • Yes, all fine in the kitchen and shower
    – K Mac
    Commented Dec 20, 2022 at 19:56

1 Answer 1


If holding your thumb over the sink spout caused hot water to flow to the toilet, then the cold-water connections are OK at least from the sink and toilet back down to wherever the two lines diverge.

Someplace between their junction and the main valve, either a pipe is clogged or a valve got closed.

Trace the pipe back from the toilet, making sure all valves are open.

If that doesn't help, then seeing which other lines do and don't run normally may help you narrow down where the problem must be.

Around this time of year, I would suspect that someone may have been trying to turn off water to the outside garden-hose tap and closed the wrong valve.

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