The cultural-natural reservation “Orheiul Vechi” benefits from very rich aquatic natural resources, these representing an essential element of the complex. By specific means they have been capitalized by man since ancient times, thus constituting another type of combination of the natural phenomenon with the cultural one.The practical necessities forced the man from the Orheiul Vechi area to invent and build various technical systems for extracting drinking water, these having the shape of wells of different types and depths or arranged water springs.From a hydrogeological point of view, the Orheiul Vechi area is a component part of the Moldavian artesian basin. Within the limits of the historical-natural complex Orheiul Vechi, six aquatic horizons are highlighted:
- The horizon of alluvial, alluvial-deluvial deposits of Holocene age (al-adQIV).
- The horizon from alluvial deposits of Eopleistocene – Upper Pleistocene age (alE-QIII).
- Sporadic waters from eluvial, eluvial-deluvial deposits of the Upper Pliocene-Holocene age (e, ed, N23-QIV).
- The aquatic horizon from the alluvial rocks of the Upper Pliocene (aN22-3).
- The aquatic horizon from the rocks of package III of the middle Sarmatian (N1S23).
- The aquatic horizon of the middle and lower Sarmatian (N1S1– N1S22).