In an older island home the leak is rarely the expensive part. What it soaks usually is.
Located before anything is opened
Listening equipment and thermal imaging narrow a leak to a small area first, which matters enormously in a house with original plaster and panelling. Exploratory holes in irreplaceable material are the expensive mistake, not the plumbing.
Look underneath first
If your home is raised, walk under it. Damp patches, green staining on fittings, drips and rust marks on pipe supports are all visible without any equipment at all, and that simple look answers the question a surprising amount of the time.
The one-minute test
Close every tap and anything using water, including the outdoor shower, then watch the meter. If it moves, water is going somewhere it should not.
Humidity turns leaks into rot
Island air keeps damp timber damp. A slow leak onto framing beneath an old house becomes a structural problem faster than it would inland, and that repair is far larger than the pipe that caused it.