Beyond reliability: a resilience journey in urban water systems

Urban water systems operate in an environment shaped by deep uncertainty, cyber-physical exposure, and dependencies on other infrastructures. Reliability-dominant planning remains necessary, but on its own is no longer sufficient under conditions of hydro-climatic non-stationarity, shifting demands, ageing assets, and hybrid disturbances. This review argues for a consequence-first operationalisation of resilience in which the objective is continuity of essential service and a key test is whether consequences remain bounded and recovery is credible. It treats stress-testing as diagnostics, using ‘resilience profiles’ to examine how systems degrade, where thresholds are crossed, and how recovery unfolds across different futures. It traces how literature evolved from whole water cycle planning to cyber-physical consequence and then to cascade-aware continuity under dependencies. Building on Safe & SuRe and later work, it argues that resilience claims should be supported by auditable evidence: service thresholds, stressor registers, consequence metrics, recovery assumptions, and disclosure of cross-sector dependencies.