The TPR valve, an acronym for Temperature, Pressure Relief valve. Is a safety device installed in your water heaters. This safety device is designed to "open" and allow pressurized water and steam heat to escape under certain conditions. Water heaters are designed to heat water. They accomplish this by using either electric or a gas such as propane or natural gas. As they heat the water, pressure also builds up. If there was no TPR valve, and the pressure continues to build without a way to escape, a situation called a BLEVE (boiling liquid, expanding vapor explosion) can occur. This has the potential to create a deadly explosion. Ensure your water heater has a TPR valve installed. Furthermore, these TPR valves are supposed to be piped so that in the event the valve opens, will direct the super-heated water/steam safely out by directing it to the ground or directly to the outside.