Metallurgical failure analysis was requested after a hot water valve failed, flooding a residence. Visual, microscopic, and x-ray examination of the failed valve indicated that the cause of the leak was a damaged neoprene washer. Analysis revealed that the washer had been damaged by heat during initial valve installation causing it to fail. The heat damage of the neoprene washer was determined to be due to improper installation of the valve by the plumber who originally installed the valve. A close-up view of the failed hot water neoprene washer is shown in Photograph A below.