In accordance with one embodiment of the present invention, a seal for a surge relief valve includes a) a valve housing having a flow inlet and a flow outlet; b) an annular retainer for coupling a plug to an interior of the valve housing, the retainer having a first end oriented toward the flow inlet and a second end remote therefrom; c) the plug having a first end oriented toward the flow inlet and a second end remote therefrom, the plug having a mating junction for coupling with the second end of the retainer, the plug having a first countersink, a second countersink, a first lip defined between the first and second countersinks and a second lip adjacent the second countersink; and d) an annular plug seal having a first end oriented toward the flow inlet and a second end remote from the first end for mating with the second countersink and a lip that abuts the second end of the retainer.