There is provided a heated livestock waterer having a heater chamber, a heater disposed in the heater chamber that, in operation, generates at least heated gas, and a water reservoir having at least one sidewall that is in thermal communication with the heater chamber, the water reservoir having an animal watering section and a covered section covered by a lid, the lid and the covered section defining an air space that is in fluid communication with the heater chamber via an air passage, the air space having a vent to atmosphere.
