The Holy well was the place where the ancient Sardinian people used to adore the Water, principal element of Nature and that also has got healing qualities. If someone was supposed to be a thief he had to pass the water judgement: his eyes were wet with the well water. If guilty, he would have become blind if innocent his eight would have become better than at first. The holy wells' were usually built next to villages.
The archaeologists have found a lot of pieces of  pottery, which maybe were gifts for the Divinity