A redundant historic water cistern, partly sunken into the ground, was renovated and adapted to serve the main house (Constantia house). With mass in-situ concrete walls (the first of its kind in South Africa) and a roof of vaulted bricks, the 100-year old structure had cracked and was unsafe. The unstable part of the structure was demolished allowing the creation a walled kitchen garden and space for planted grey-water recycling tanks. Inside the remaining cistern are rainwater tanks fed from the roof of the house, a purification plant for potable water and irrigation tanks fed from a borehole. The roof supports photovoltaic panels with invertor and batteries below in the cistern.