The hot water overflow is recognized as pressure relief valve. This safety unit will vent a hot water heater in case the pressure turns way too high. For this reason, the overflow can’t be replaced or compromised by using a plug. A functioning safety valve ought to be put on all domestic hot water heaters. However, if you simply identify certain things amiss with all the hot water heater overflow, you are able to fix the problem by replacing or repairing the valve.