The proper name of the Healing Springs would be "The Healing Springs of Promalle", Promalle being the name of the goddess of Mercy. Hence why Marzos calls the Springs 'holy'.

Granted, this would imply that Promalle herself would have something to say about all this. But, in reality, nobody's REALLY sure whether or not the waters are blessed/controlled by her directly or not. It could just be a naturally occuring magic water. Still, it is pretty cool.