Immaterial objects cannot normally be affected by material objects. Water is material.
An Immortal doesn't need to breathe, for instance, as its existence has transcended the material world and life. Neither do they age, which is how Quintessence from the air of the gods (Aether) grants immortality.
I agree with giving a use for more copies of Flooding, though it's enough with removing one slot per copy and starting at 5.