Artificial intelligence, connected sensors and big data analytics are reshaping how cities manage drinking water and treat sewage, but a new study finds that critical gaps in sewage infrastructure, cybersecurity and equity threaten to limit the benefits of that transformation. A systematic literature review published in the journal Water mapped how Industry 4.0 technologies are being deployed across urban water and sanitation systems. Researchers at Santa Catarina State University (UDESC) in Brazil analysed 208 peer-reviewed articles published between 2019 and 2024, covering applications from water distribution and leak detection to wastewater treatment and consumption measurement. AI and IoT lead the way, but not uniformly Three technologies dominate the evidence base. Artificial intelligence accounted for 43% of all recorded occurrences, followed by big data and data analytics at 26.5% and the internet of things (IoT) at 19.8%. Together, they represent nearly 90% of all identified applications. IoT stood out as the most versatile, being the only technology documented across every application area examined: from water distribution and wastewater treatment to sewage collection and smart metering. In practice, networks of sensors embedded in pipes, pumps and treatment plants provide operators with real-time data on pressure, flow rates and water quality that traditional monitoring methods cannot match. One study cited in the review found that IoT-enabled wastewater monitoring systems achieved efficiency levels approaching 88.7% and recycling rates of up to 96.3%. Another recorded a 95% success rate for IoT-based smart metering in detecting residential leaks. While Industry 4.0 technologies are moving sanitation services from reactive to predictive management, stronger policy support, investment in sewerage infrastructure and sector-specific cybersecurity frameworks are needed Artificial intelligence is being applied to leakage control by detecting anomalies in pressure and flow data, enabling faster localisation of losses and reducing non-revenue water. In wastewater treatment, the second most common