A PC can hold his breath so that he does not drown.
DrowningAny character can hold her breath for a number of rounds equal to twice her Constitution score. If a character takes a standard or full-round action, the remaining duration that the character can hold her breath is reduced by 1 round. After this period of time, the character must make a DC 10 Constitution check every round in order to continue holding her breath. Each round, the DC increases by 1.
When the character finally fails her Constitution check, she begins to drown. In the first round, she falls unconscious (0 hp). In the following round, she drops to –1 hit points and is dying. In the third round, she drowns.
Unconscious characters must begin making Constitution checks immediately upon being submerged (or upon becoming unconscious if the character was conscious when submerged). Once she fails one of these checks, she immediately drops to –1 (or loses 1 additional hit point, if her total is below –1). On the following round, she drowns.
It is possible to drown in substances other than water, such as sand, quicksand, fine dust, and silos full of grain.
They start to drown. Pretty harsh! If you're nice, the moment of dispelling is when you start counting how long they can hold their breath (hand-wave the water in their lungs).
My drow PCs ran into this when attacking a deep one city... the wizard considered casting antimagic field until he realized (1) that would negate his water breathing, (2) the effect is centered on him and moves with him, so he can't breathe again until he dismisses the field...
I forgot that you are actually breathing water per the spell. I was thinking of it as you breathing underwater, but not taking water in. Thanks Sean.
