An IoT gateway is a device that connects smart sensors to the cloud, enabling communication between the physical world and digital platforms. In rainwater harvesting systems, it collects data from level sensors, flow meters, and pumps, then sends that information to monitoring dashboards. It also processes data locally, ensuring real-time alerts and efficient water management. IoT gateways help reduce water wastage, automate rainwater storage, and ensure timely maintenance. They’re the backbone of modern, data-driven rainwater harvesting setups.