Victorian terraces share joists as well as walls. A leak under your bathroom floor can track along a joist, cross the party wall line and come through your neighbour's ceiling before it has marked anything of yours. By the time anyone knocks on a door, the water has been going for a while. It turns a plumbing job into a conversation with the people next door, and the fastest way to keep that conversation civil is to locate the leak precisely instead of guessing.
So we trace before we open. Thermal imaging picks up heating pipes through floors — a leak reads as a warm plume long before it is a damp patch. Acoustic equipment finds pressurised leaks on cold mains where there is no heat signature to look for. Between the two we can normally mark the spot within an inch or two and lift one board rather than a floor.
The most common Sale call is not dramatic. It is a boiler that keeps losing pressure and a filling loop somebody has been topping up for a year. That is a leak, and every top-up is pulling fresh oxygenated water into a sealed system that is not supposed to see any — which corrodes it from the inside while you are being helpful. If you are refilling more than about once a year, ring someone.
The other thing soft water does here is worth knowing. Trafford water is soft, so there is no protective scale layer inside old pipework, and on Victorian stock that shows up as pinhole corrosion in old copper. It is the classic slow leak on this housing type — a weep rather than a burst, invisible for months.
