It is part of the historic resources of the city of Oviedo and the Kingdom of Asturias, designated World Heritage by UNESCO. It was built during the reign of Alfonso III the Great (866-910) and protects a natural drinking water spring that rises directly out of the ground. It is collected in a pool covered by an ashlar structure with a rectangular floorplan and an arch with a stilted barrel vault, and finished in a gable roof.
The front bears a sculpture in relief of the Victory cross with the alpha and omega hanging from its arms. The semicircular arch is cambered and divided into large keystones. Some of the ashlars have religious inscriptions.