What Is a Hot Water Expansion Tank Used For?

Your home may have a hot water expansion tank attached to your hot water or boiler system. Do you know what it is there for? The purposes of a hot water expansion tank can be easily explained.

Reduce Overflow in Water System

Hot water expands. When a boiler system is activated to heat up a home the water actually boils. Consider an automobile radiator and how it behaves when it overheats. The water spews out from the radiator in order to vent the closed system. The purpose of an expansion tank is to eliminate this overflow from occurring.


The hot water expansion tank is a safety device for a hot water system. If hot water expands to the point where the boiler explodes, severe injuries can occur. There is also the chance of water leaks causing minor hazards like slipping.


The hot water expansion tank is pressurized and only allows the overflow of water that is necessary to reduce the pressure in the boiler system. This enables the heater system to continue to run properly, keeping your home comfortable while still ensuring a safe and effective system.