Groundwater & Basement Water Intrusion in Aventura, FL

That is how a tower behaves. Supply and drain risers run vertically through a stack, and a break at any point sends water down through the floor assemblies below rather than out into the unit where it started. Drying has to cover every unit the water passed through, which means access to several homes at once. Getting the association involved on day one is usually faster than negotiating unit by unit.

That depends on the governing documents rather than on the physics, and the two rarely line up. As a rule the association owns the common elements, including risers inside walls, and the owner owns what is inside the unit. Water that started in a common riser and damaged unit finishes therefore splits across both. The practical advice is to document the source and the path before anything is opened up, because that record is what the split is argued from later.

On fill this close to tidewater that is usually the tide rather than a plumbing problem. Seasonal high tides raise the water table and close the drainage outfall, so water surfaces at the lowest slab whether or not it has rained. It recedes with the tide. It is worth tracking against the tide tables rather than the forecast, because a plumbing investigation into a tidal event finds nothing and costs a week.