Lining of pit latrines is of growing interest in many developing countries where improved and permanent non-sewered sanitation is being installed. In particular, where mechanised emptying by powerful suction tanker is intended, an effective permeable lining is necessary to prevent ground erosion under the latrine and eventual collapse of the floor and superstructure. BRE has developed a moulded concrete lining block which, although originally designed to line pit latrines, could also be used to line soakaways and shallow wells.