Water security is a central aim of water policy. Indicators exist to measure water security at the national level but these national averages do a poor job of reflecting the challenges facing policy-makers because of water’s fundamentally local nature. This paper focuses on measuring water security at the city level where tailored indicators can help policy-makers to identify threats to security and associated policy gaps. It proposes a systematic framework for the conceptualisation of urban water security and defines a set of indicators that can be adapted to the characteristics of a specific city. The selection of detailed indicators is based on a thorough review of each city’s water security and validated through stakeholder consultation. The approach is piloted in two cities – Singapore and Hong Kong – using data for a 20-year period.