Interests sit at the asset layer rather than the technology layer: the store itself, the lined basin, the recharge field, the network, the concession and the abstraction right. These are assets with design lives measured in generations and with regulated, indexed revenue — a poor match for capital that must exit inside five years, a natural one for capital that has held railways, energy and fuel across six. The jurisdictions run from the Baltic to the Maghreb, the Mediterranean islands, the American interior and the Nile; drought and flood do not arrive together across basins that far apart.
Exposure is spread along the chain — catchment and intake, storage, treatment train, brine handling, distribution, metering — because the binding constraint moves. One decade of scarcity is solved at the membrane; the next at the store, or at the leak, or in the permit. A holder present at several points in the chain need not be right about which technology prevails, only about the direction of demand, which in this field has not reversed.
The scarce instrument is the right, not the steel. Abstraction licences, recharge permits, riparian and transboundary allocations, outfall consents: granted rarely, priced politically, seldom traded once held. In a reordering of states and currencies, an allocation written into a treaty or a long concession tends to outlive the institution that issued it — an argument for holding such things through a family, whose horizon matches the asset's, rather than through a vehicle whose horizon does not.
