What this job involves on Seabrook depends entirely on whether you are in a raised house or a ground-level villa.
Raised homes are the easier case
Where a house stands on pilings, the pipework runs underneath in open air. No concrete to break, nothing to guess at, and a leak that would be a serious job on the mainland is often found and repaired in one visit.
Ground-level villas
Many of the original villas sit on slab. There we use listening equipment and thermal imaging to pinpoint a leak before opening anything, which matters when the floor above the pipe is finished and the home next door shares a wall.
Rule out irrigation first
Before assuming anything under the house, isolate the irrigation. A failed line or backflow preventer produces exactly the same rising bill with nothing wrong indoors, and it is a far simpler repair.
In an empty home you will not hear it
The usual early warning — water running when everything is off — only helps if somebody is standing there. It is the strongest argument for an automatic shut-off valve on a seasonal property.