Definition
Night Minimum Flow and Leakage Analysis relies on Night Minimum Flow (MNF): the minimum instantaneous or hourly flow observed during low water use periods in a District Metered Area (DMA). Ideally, residential and most non-residential users consume almost no water at night; at this time, flow mainly reflects background leakage in the network, tank seepage, illegal use of fire hydrants, or unregistered consumption.
By reporting hourly or finer granularity curves through IoT water meters, zonal flow meters, and other devices via cellular networks, the platform can compare against historical baselines and exclude seasonal and weather factors, allowing early detection of new leaks or meter calibration drift due to DMA boundary adjustments. IoT SIM cards are suitable as the main channel or backup when wired private networks are unavailable, and can work together with SCADA, DMA, and leakage management platforms.
Technical Features
The collection frequency should balance with battery life: generally, zonal aggregation can be reported on an hourly basis, while zones sensitive to leakage can increase reporting frequency or report more frequently during night windows. Time synchronization, daylight saving time, and meter replacement events should be tagged on the platform to avoid misinterpretation of sudden curve changes.
SimtoLink IoT SIM cards provide wide-area cellular access for terminals, supporting combinations such as private network, public network, multiple APNs, and VPDN, facilitating unified authentication, whitelisting, and traffic management; in engineering, capacity planning should be carried out considering heartbeat, reporting granularity, and data plan tiers, and methods for weak network reconnection and log retention should be reserved.
Use Cases
Urban water supply leakage control, zoned metering, and water-saving assessment; similar methods can also be used to identify hidden leakages in rural large-scale water supply and industrial park closed pipe networks. SimtoLink can provide connectivity for smart water meters and zoned monitoring terminals.
When linked with active leak detection, pressure management, and secondary water pump room monitoring, DMA numbers and data standards should be unified, distinguishing between "connected online" and "curve quality qualified" (missing data, freezing, backflow) to facilitate troubleshooting and KPI statistics.
Deployment and Operation Recommendations
During the project implementation phase, enterprises should bind the IoT SIM card numbers to device serial numbers, installation locations, power supply methods, and maintenance responsible persons one-to-one, and sync this information into the asset and operation system to form a traceable link from card issuance, modification, activation, suspension to eventual cancellation. For equipment involving cross-province allocation or cross-border delivery, roaming charges, real-name registration policies, and local data compliance requirements should be evaluated in advance. It is recommended to choose solutions with predictable costs that support remote network switching or eUICC, reducing the frequency of on-site disassembly, and reserving spare cards and emergency replacement processes to shorten fault recovery time. For terminals received in bulk, it is recommended to perform sampling network verification covering connectivity and charges before activating the entire batch, to reduce rework costs.
In terms of cybersecurity, it is recommended to configure dedicated APN or VPDN tunnels for production or critical infrastructure terminals, converge north-south traffic to enterprise-controllable boundaries, and link with identity authentication, bastion host remote maintenance, and operation auditing; for remote control and parameter writing capabilities, hierarchical authorization, time windows, and dual-person review should be set. Regular drills for weak network and primary/backup link switching should be organized, recording latency, packet loss, and recovery time as technical references for MLPS (Multi-Level Protection Scheme) assessment, industry regulatory inspections, or internal risk control reviews. For third-party outsourced operations, minimum permissions, session recording, and key custody responsibilities should be clarified to avoid account sharing.
In daily operations, card management platforms should be used to continuously track online rates, abnormal traffic, dormant terminals, and data plan utilization, integrating alarms with the ITSM work order system to achieve automatic ticket assignment and closure. SimtoLink can split data pools for enterprises by factory, line, or business domain, providing bulk device suspension/resumption, API integration, and billing allocation capabilities, supporting visibility, control, and sustainable cost reduction at large-scale points, while aligning card management insights with project budgets and cost centers to improve transparency.