Finding a hidden water leak

[MikeToll]

Thank you for the extensive post - that's exactly the big picture I'd not been grasping and great to have that (obvious to many no doubt) way of narrowing down the problem.

I think I've got a reasonable feel for where the various pipes go - especially the heating as I did some thermal imaging a while back so I'll press on with diagnosis.

Thanks again to all contributors.

 

[morg]

Could it be electric shower / mixers weeping internal valves which isn't obvious i. e a long/intermittent drip could go unnoticed

Can stopcocks weep in the open position (from the gland nut / turn shaft)

 

[YorkshireMidge]

Could it be electric shower / mixers weeping internal valves which isn't obvious i. e a long/intermittent drip could go unnoticed

Can stopcocks weep in the open position (from the gland nut / turn shaft)

Both are possible. Though in the case of an electric shower, whoever fitted it *ought* to have sealed around the mains water pipe - so any leak anywhere in the body of the electric shower would run out the bottom of the casing and down the shower wall, rather than running down the pipe and into the wall.

The O/P has turned the stop cock off as part of his diagnosis (see his original post) so I assume he would have noticed if it was dripping given the amount of water involved.