Cape Town, South Africa

Facing a 1-in-300-plus year drought, metro Cape Town (4 million people) deployed a full emergency demand management package: Level 6B restrictions capping use at 50 liters per person per day from 1 February 2018, steep block tariffs, network pressure management (saving roughly 10% of demand), ~250,000 flow restrictors installed on over-consuming connections, a weekly public dashboard, the green-dot City Water Map showing household compliance, agricultural water transfers, and the 'Day Zero' deadline naming the date taps would run dry. Demand fell from ~1,200 ML/day (February 2015 peak) to 511 ML/day (March 2018). Day Zero never arrived. Caveats for replication: informal settlements (~13% of population, ~4% of consumption) were already below the 50 L cap, so the restriction instruments targeted wealthier users in practice; the City Water Map raised privacy concerns; and the demand collapse caused a volumetric revenue shortfall requiring post-crisis tariff restructuring after a proposed drought charge was dropped under public opposition.