Access to reliable water quality monitoring remains a significant challenge in rural and underserved regions, where laboratory-based analyses are often constrained by logistical and economic limitations. This study presents the design and functional laboratory-scale implementation of a low-cost IoT-based monitoring platform intended to support the digitalization of decentralized water treatment and water management through remote assessment of pH, temperature, electrical conductivity, dissolved oxygen, and turbidity. The proposed architecture integrates commercial sensors within a valve-controlled hydraulic chamber that performs intermittent fill–retain–measure–drain cycles, a Pycom LoPy 4.0 acquisition unit, LoRaWAN-based data forwarding, and cloud-based visualization. Functional testing demonstrated successful end-to-end integration of the hydraulic, sensing, communication, and visualization subsystems under controlled prototype conditions. The minimum demonstrated operational cycle was approximately 90 s; however, this value corresponded to the shortest functional testing condition rather than the intended routine monitoring interval, which incorporates a configurable inactive period between consecutive measurement cycles. The results demonstrate the feasibility of integrating low-cost sensing technologies, intermittent hydraulic sampling, and LoRaWAN connectivity into a laboratory-scale engineering prototype for decentralized water quality monitoring. The proposed platform should therefore be regarded as a functional proof-of-concept that establishes the technological basis for future metrological validation, long-term field deployment, and integration with decentralized water treatment systems rather than as a fully validated monitoring instrument.