The Starcia valley has water in abundance. Besides the Starcia, which flows into the river Orcia, there is also another stream named Colombaiolo that comes down from Villa Tolli. It joins the Starcia at a short distance from the Romanesque bridge next to the old mill of Castelnuovo dell’Abate. Moreover, four water-stratum pass under the church, at a depth that varies from ten to twenty meters. We know too that water coming down from the Arcangela fountain situated at that point where the slopes of the hill Castellare begins, was conducted to the monastery to finish up in the cloister. Curiously enough, already in the 16th century the water had been conducted into the church, and from a basin on the inside, then poured forth into a sarcophagus, which stood on the north side of the cloister.