Motorized main-line valve paired with a flow/pressure sensor, learning normal household use and auto-shutting off on anomalous flow (burst pipe, freeze, continuous drip), catches and stops leaks in real time, including ones too slow or remote to notice manually. Depends on continuous power and, for most commercial products, a network connection for alerts; sealed electronics aren't field-repairable.
Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.
none
No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.