Water loss is one of the biggest operational challenges facing NZ councils. District metering divides a water distribution network into discrete, measurable zones and uses flow meters at the boundaries to monitor supply and detect losses.
A District Metering Area is a hydraulically isolated section of a water distribution network with a defined, metered boundary. All water entering the DMA passes through one or more flow meters at the boundary, giving the network operator a continuous measurement of supply into that zone.
By comparing the volume of water supplied to a DMA against the volume of water accounted for (through customer meters and known uses), the operator can calculate the apparent loss within that zone, a key indicator of leakage. DMAs are typically designed to serve between 500 and 3,000 connections.
Abnormal night flow in a specific DMA indicates a new leak, enabling targeted investigation rather than network-wide searches.
Granular demand information supports network planning, pressure management, and capital investment decisions.
Quantifying and actively managing water loss is increasingly important under the NPS-FM and Three Waters reforms.
DMAs enable PRVs to be tuned by zone, reducing average operating pressure and the rate of leakage and pipe failure.
Flow meters are installed at DMA inlet points (measuring total supply into the zone), outlet points (where water exits through a second metered point), sub-zone boundaries (for finer-grained leak location), and bulk supply points (measuring water from treatment plant to distribution zone).
For DMA metering, electromagnetic (mag) flow meters are the standard choice, high accuracy at low flows, bidirectional measurement, MODBUS/HART/pulse outputs for SCADA, and low-maintenance designs suited to buried chambers with limited access. Interval data logging (typically 15-minute intervals) is required for minimum night flow analysis.
The value of district metering depends entirely on the quality of the data it generates. Modern DMA programmes use telemetry to transmit meter data to a central platform in real time, enabling continuous monitoring of minimum night flow, automated alerts, historical trend analysis, and integration with SCADA and asset management systems.
NZ Flow Group's our cloud-based water management platform can support telemetry data collection and hosting for DMA applications. Contact us to discuss data management options for your network.
A hydraulically isolated section of a water distribution network with a defined, metered boundary. All water entering passes through flow meters, enabling continuous measurement of supply and calculation of leakage within that zone.
Minimum night flow (typically 2–4am) represents the lowest demand period. Any flow above expected legitimate night use is attributed to network leakage. A sudden increase indicates a new leak has developed in that zone.
Sometimes, but they may not be at the right hydraulic points, may lack appropriate accuracy or communication outputs, or may not have data logging capability. NZ Flow Group can assess your existing meters.
District metering principles are primarily applied to water supply networks. Wastewater flow measurement focuses on treatment plant influent/effluent metering, pump station monitoring, and trade waste discharge measurement.
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Get in touchWe supply and install flow meters for council water network applications across Canterbury, including DMA metering, bulk supply metering, and pump station measurement.