Water

IsPlayerOnWater(playerid)
{
    new Float:x, Float:y, Float:z, Float:retx[2], Float:rety[2], Float:retz[2], Float: retdist[2], modelids[2];
    GetPlayerPos(playerid, x, y, z);
    new collisions = CA_RayCastMultiLine(x, y, z + 0.7, x, y, z - 0.7, retx, rety, retz, retdist, modelids, 2);
    //---
    if (collisions)
    {
        for(new i = 0; i < collisions; i++)
        {
            if (modelids[i] == 20000)
            {
                return true;
            }
        }
    }
    return false;
}

IsPlayerUnderWater(playerid)
{
    new Float:x, Float:y, Float:z, Float:retx[10], Float:rety[10], Float:retz[10], Float: retdist[10], modelids[10];
    GetPlayerPos(playerid, x, y, z);
    new collisions = CA_RayCastMultiLine(x, y, z + 0.7, x, y, z + 1000.0, retx, rety, retz, retdist, modelids, 10);
    //---
    if (collisions)
    {
        for(new i = 0; i < collisions; i++)
        {
            if (modelids[i] == 20000)
            {
                return (true);
            }
        }
    }
    return false;
}