The Macta River basin in Algeria is under pressure. A water accounting of the basin demonstrates the severity of the crisis, with a net water depletion rate estimated at 93-142%, depending on the assumptions made. This reflects the overexploitation of the aquifers whose annual depletion is estimated at between 86 and 126 Mm(3). This paper first discusses the causes of basin overbuilding and the over-allocation of water, and then analyses the economic, social and environmental consequences. It calls for a stricter water accounting of river basins in Algeria as the 2030 Agenda for Sustainable Development and its SDG 6 are implemented.