Water Heating Systems Most modular home factories include an electric hot water heater in the price of the home. Depending on where your hot water heater is located in your home will determine if the unit is installed by the factory or not. Modular homes built on full foundations with the water heater located in the basement will have to have the water heater installed on site by others. Where as a water heater located in one of the modules, the water heater could be connected. Regardless if the water heater is installed in the factory or on site, you will need to have the water lines air tested for 120 psi. | 
