A tankhouse (also spelled tank house or tank-house) is a water tower enclosed by siding. Tankhouses were part of a self-contained domestic water system supplying the house and garden, developed before the advent of electricity and municipal water mains. The system consisted of a windmill, a hand-dug well and the tankhouse. The windmill pumped water from the well up into the tank at the top of the tankhouse, from where it flowed down under gravity pressure to the house and garden. The system used no fuel or electricity.