[Kraeror]

I made it by myself for seconds and I think it will work!
Here is it (on the top of your script):

PHP Code:

bool: IsPlayerInWater(playerid)
{
    new Float: pPosition[3];
    GetPlayerPos(playerid, pPosition[0], pPosition[1], pPosition[2]);
    if(IsPlayerInRangeOfPoint(playerid, 10000, pPosition[0], pPosition[1], 1-10000))
    {
        return true;
    }
    return false;
}