Mounted in a bottom side of a water discharge device of a refrigeration/air-conditioning system for collecting waste water, a vermin-protective, high-strength and high beauty water pan is disclosed to include a bottom portion, and an upright peripheral wall extending along the border of the bottom portion and having at least one overflow port. The upright peripheral wall has a part curved inwards, defining a recessed open chamber, a recessed wall portion that surrounds the recessed open chamber, a bridge wall portion that suspends above the recessed open chamber and has the topmost edge thereof higher than the topmost edge of the recessed wall portion, and a plurality of ribs that are connected between the recessed wall portion and the bridge wall portion and divide the space in between the recessed wall portion and the bridge wall portion into multiple overflow holes that form one overflow port.