The actual repair, for example of a leaking connection, is usually manageable. The consequences are what make it expensive: soaked screed and wet walls that need technical drying, damaged equipment, spoiled stock and rooms that cannot be used for weeks. In apartment buildings, affected tenants come on top.
Potential damage depends on factors including the amount of escaping water, its path and the time until someone intervenes. A water alarm can help detect a leak sooner, including at night or over the weekend. A prompt response requires agreed recipients, access and actions.
For dealing with insurers and contractors it also matters when the damage began. The alarm history shows when the sensor first reported water and who was notified.