This paper presents an adaptive rainwater-harvesting (RWH) system based on a rainwater-collecting unit that (1) ascertains baseline water-quality in its collected rainwater via Ph- and turbidity sensors, and (2) redistributes it to designated toilet-tanks and/or irrigation points. Each unit is integrated with an XBee S2B antenna to enable cost-effective and energy-efficient mesh capabilities for inter-unit communication when two or more units conform the system. Moreover, each unit is also an Internet-of-Things (IoT) device that transmits water-tank levels and sensor-data to a local supervising microcontroller (MCU) via Open Sound Control (OSC). This MCU is, in turn, capable of communication with a cloud-based data plotting / storing and remote-control platform - viz., Adafruit IO - via Message Queueing Telemetry Transport (MQTT). The interface with Adafruit IO enables a remote administrator (a) to monitor water-tank levels and sensor readings, and (b) to execute manual overrides in the system - for example, any or all of the units may be shut-down remotely. When only one unit conforms the system, its water-tank services the toilet-tanks and/or irrigation points connected to the unit. When two or more units conform the system, their water-tank outputs are physically linked, enabling any unit to contribute to the servicing of a variety of connected toilet-tanks and/or irrigation points. In both single or multi-unit configurations, water redistribution is impartial to any end-point at initialization, yet over time the system identifies which end-point(s) require(s) water with a higher frequency and selectively prioritizes servicing to it/them to guarantee prompt refill / supply. The present work is part of ongoing developments of features and services that attempt to imbue the builtenvironment with intelligence via Information and Communication Technologies (ICTs).