I have some DIY knowledge, but it falls somewhat flat when it comes to plumbing.

I noticed there was a leak in the airing cupboard and tracked it down to this innocuous pressure guage. I have no idea what the surrounding valves do (but there's a water heater in close proximity so I assume that some of them have a bearing on this). The house mains are also very close by.

I am collecting the water that is dripping beneath the guage, but I am concerned. If this is due to high water pressure is there risk of anything worse happening? What actions should I take? (calling a plumber on Friday night, during lockdown, is clearly not an option)

pressure guage

Due to request the area immediately above this photo is visible in the following photo. valves

Where the teal/turquoise pipe is immediately above the leak, the red pipe I think is the mains, and the yellow one connects to the top of the water tank.

I can't really see below the area with the leak as the water tank itself is in the way (and it is really big).

This area is a confusing mash of pipes but on closer inspection I am fairly certain that the pipe featuring the pressure valve is directly connected to the water heater in such a way as to suggest it brings cold water from the attic to the water heater (via that white and grey braided... hose?... with the grey taps at either end).

I do not know if the pipe above the leak connects to the red pipe... it disappears behind wood panelling... but I can feel it... it runs top to bottom parallel to the red pipe, it has a branch witch features our pressure valve. The pipe itself is slightly wet, both above and below this branch.

  • Can you add a few more pics showing where the water is coming from and where it's going to? "There's a water heater in close proximity" doesn't indicate whether the line comes directly from the heater.
    – FreeMan
    Commented Nov 6, 2020 at 18:54
  • @FreeMan picture added, with some explanation
    – Stumbler
    Commented Nov 6, 2020 at 21:31
  • [read in stoner voice]: Man, dude, that's really busted man, bummer, total downer and a drag, dude. .... OK seriously now, it's probably the bourdon tube inside the gauge that's leaking. By design they have to be thin enough to flex and thereby move the needle on the gauge. They do fail. Not a true answer, but a start. Commented Nov 6, 2020 at 22:45

1 Answer 1


First you should determine whether the gauge itself is the source of the leak. It is common for a leak to develop at the threaded fitting or elsewhere and to run down and drip from a different low point.

That type of gauge has an internal part called a Bourdon tube made of relatively thin (usually metal) material. The tube contains the process fluid (water) at system pressure and deforms according to the pressure. That deformation creates movement that is represented on the gauge dial. It is not uncommon for the tube to fail and leak which does not (necessarily...) indicate a system problem or dangerously high pressure.

If this is due to high water pressure is there risk of anything worse happening?

YES- of course, overly high pressure can damage fixtures, valves pipes, appurtenances, etc.

What actions should I take?

Remove and replace the gauge and start monitoring the system for problems. Take pressure readings at various times, etc. If you know your normal system pressure then you should be capable of recognizing abnormal pressures. In the end, if you have a pressure issue that you can't properly diagnose, you will need to get a plumber in there.

  • Note- some gauges are filled with fluid by design, to help dampen vibration. I can't tell whether or not yours was filled deliberately but I suspect not because those are not often found in residential service and are typically rather expensive. Commented Nov 6, 2020 at 19:01

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