Up the road from the Gymnasium lies the Kastalian spring. These waters were carried to the sanctuary of the oracle and were used to cleanse both priests and pilgrims before they entered the temple of Apollo. The spring was decorated with a facade as well as niches for votive offerings.

In Archaic and Classical times, a subterranean fountain with a square was used.

Original Kastalian Spring Archaic and Classical Kastalian Spring