what is while (my.x) ?

anyway , just use a region or the min max size to determine if the player has entered the area .

without the actual code which you use to detect whether the player is inside the water ,plus how you set up that events (I am assuming) no one will know WHY what's happening.

we don't even know if your windows system sounds has a sound assigned to the relevant beep (I dont know if GS has its own but usually its taken from system sounds) , I assume there's nothing wrong with the sound aspect as is normal but you really need to provide the relevant code , for people to help you .