Non-revenue water loss analysis is the work of establishing how much water entering a network is billed and how much of the rest is physical (real) loss, such as leaks and bursts, or commercial (apparent) loss, such as meter errors, misreads and illegal connections. It starts with a water balance, then uses district metering and night flow to locate losses.
Key takeaways
- Non-revenue water loss analysis splits unbilled water into physical losses (leakage) and commercial losses (meters, misreads, illegal connections).
- According to Türkiye's Ministry of Agriculture and Forestry, the average water loss rate was 31.6% in 2024; the 2028 limit for metropolitan municipalities is 25%.
- Losses are located by dividing the network into district metered areas (DMAs) and tracking each zone's minimum night flow.
- Automatic meter reading alone cuts only part of commercial loss; physical loss needs pressure management and active leak detection.
- The first step needs no new investment: build a water balance from the last 12 months of production and billed consumption.
How does the non-revenue water problem look inside a utility?
In most utilities, the loss rate is calculated once a year as the difference between water produced and water billed. The number is high, but on its own it says very little: which district, pipes or meters, day or night? Crews go out when a burst is reported; leaks that never reach the surface can run for months or even years.
Commercial losses are even less visible. An old meter stops registering at low flow, a reader enters an estimate at a locked door, and an illegal connection is only found when someone reports it. None of these losses is fixed by repairing pipes; they need measurement and reading discipline.
In short, the problem is not that the loss rate is high. It is that nobody knows where the loss is or what kind it is. And unknown losses can only be reduced by guesswork, which means expensive, scattered field work.
What does water loss cost, and what are the legal targets?
Türkiye's water loss rate is falling, but it still trails both the legal target and developed countries:
According to Türkiye's Ministry of Agriculture and Forestry, the average water loss rate in drinking water networks fell from 39% in 2015 to 31.6% in 2024, and metropolitan and provincial municipalities must bring it down to at most 25% by 2028. (Ministry of Agriculture and Forestry — Urban Water Efficiency)
On the same page, the ministry notes that loss rates in developed countries range from 8% to 24% and describes its ultimate goal as around 10%, not 25%. Among the measures it recommends are wider use of remote monitoring and control systems, district metering and pressure management zones, and minimum night flow analysis. In other words, the method is not in dispute; the challenge is implementation.
The obligation covers every municipality. Türkiye's 2014 Regulation on the Control of Water Losses in Drinking Water Systems also requires smaller municipalities to reach at most 30% by 2028 and 25% by 2033.
Every lost cubic metre has already been treated and pumped, and its energy paid for. Globally, the World Bank's assessment of non-revenue water estimates that 126 billion cubic metres of water are produced but never billed each year, costing nearly $40 billion annually in waste and foregone revenue. To measure the pumping itself and catch faults early, see our guide to remote pump station monitoring.
What is a water balance, and how are losses split by type?
A water balance is the table that splits the water entering a network by where it goes, and it is the first step in non-revenue water loss analysis. The widely used water balance approach of the International Water Association (IWA) does it like this:
| Component | What it means | Typical source | How to reduce it |
|---|---|---|---|
| Billed authorised consumption | Water that is metered and billed | Customer consumption | — |
| Unbilled authorised consumption | Permitted use that is not billed | Firefighting, parks, mains flushing | Measure and record it |
| Apparent (commercial) losses | Water consumed but not measured correctly | Meter inaccuracy, misreads, illegal connections | Meter replacement, automatic reading, theft checks |
| Real (physical) losses | Water escaping from the network | Leaks at pipes and joints, tank overflows | Pressure management, active leak detection, fast repair |
Non-revenue water is the sum of the last three rows. Without this split, every investment decision is made blind: buying meters for a network dominated by physical loss, or replacing pipes where commercial loss dominates, is money spent in the wrong place.
Splitting physical from commercial loss has a further benefit: the two cost the organisation different amounts. A physical loss costs the production, treatment and pumping of the water. With a commercial loss, the water has already reached a customer and been used; what is lost is revenue at the sales tariff. That is why cutting the same volume of commercial loss usually reaches the bottom line faster in most networks, and the difference must be factored into any payback calculation.
How do you carry out a non-revenue water loss analysis? A seven-step framework
In the field, non-revenue water loss analysis follows seven steps that move from a network-wide calculation down to neighbourhood scale:
- Verify production and inlet metering. If flow meters at sources, reservoirs and pumping stations (often linked to a SCADA system) are inaccurate, the whole water balance is wrong. Calibrate the inlet side first.
- Build the water balance. Fill in the table above for your own network using the last twelve months of production, billed and unbilled consumption. Seeing which type of loss dominates tells you where to spend.
- Divide the network into district metered areas. Create district metered areas (DMAs), zones bounded by closed valves, with inflow and outflow measured by flow meters. Comparing the water entering each zone with its customers' consumption brings losses down to neighbourhood scale. Defining these zones in a geographic information system (GIS) puts customer and network data on the same map.
- Monitor minimum night flow. Legitimate consumption is at its lowest in the small hours; if inflow to a zone at that time is higher than expected, the zone is leaking. A sudden jump in night flow is the first sign of a new burst, and anomaly detection can catch it automatically.
- Manage pressure. Excess pressure increases leakage and triggers new bursts. Pressure-reducing valves at zone inlets, with different day and night settings, cut physical losses before any repair.
- Tackle commercial loss at the meter. Prioritise old meters that have lost low-flow accuracy, read meters remotely, and link zero consumption, reverse flow and tamper events to automatic alerts.
- Measure active leak detection and repair time. Send acoustic listening teams to zones with high night flow, and record the time from report to repair for every burst. Losses fall when leaks are repaired, not just when they are found.
What all seven steps share is the need for continuous, reliable field data. Steps 4 and 6 are impossible with monthly meter reads and a loss rate calculated once a year.
What data does water loss analysis need?
Sustainable non-revenue water loss analysis depends on four data sources coming together. The meter, sensor and connectivity options that feed them are covered in our IoT & Hardware hub:
- Customer meters: at least daily readings through automatic meter reading, with hourly profiles in zones under analysis.
- Zone inlet flow meters and pressure points: continuous measurements that build the night-flow and pressure curves. The trade-offs between LoRaWAN, NB-IoT and cellular for these points are covered in our LoRa vs NB-IoT vs cellular comparison.
- Network and customer map: a GIS layer showing which customer belongs to which zone (we cover the set-up in GIS for municipalities).
- Reservoir levels: overflow is the silent item in physical losses; we explain how level data is collected in water tank level monitoring.
- Fault and repair records: when each burst was reported and when it was fixed.
When customer, zone, map and fault data stay in separate systems, the analysis has to be rebuilt by hand every time. Combined, they let you follow loss rate by zone, night-flow trends and repair times daily in a single management dashboard; our BI dashboard KPI guide explains how to design it. Use the method in how to set KPIs to choose which indicators belong on it.
How does Digital Bridge deliver water loss projects?
At Digital Bridge we handle metering devices, communications and software together. Because hardware and software come from the same team, data flows from the meter to the dashboard without hand-offs between suppliers.
- We map the current situation with you. We review your water balance data, meter stock and measurement points, and identify the most meaningful pilot zone. Technical feasibility on the hardware side is free.
- We make meters remotely readable. With our AMR meter reading system we read customer meters over GPRS/4G, LoRaWAN, NB-IoT or M-Bus depending on site coverage; the software raises alerts for zero consumption, possible leaks and unusual spikes, and passes billing data to your billing system via API.
- We bring zone measurements into monitoring. We carry inlet flow and pressure data to the centre through our remote monitoring infrastructure and, where needed, make pumping stations and reservoirs visible alongside it with SCADA. With a custom SCADA, the source code belongs to you.
- We shape the project around your organisation. For municipalities we work through our public sector and municipal solutions; for water utilities and distribution companies, through our energy and utilities solutions, designing around your existing processes and software.
The order is the same on every project: needs analysis, a written proposal setting out scope, phases and cost, a pilot zone, then roll-out based on measured results.
The logic is the same for electricity: a transformer-level energy balance narrows the area and customer-level anomaly analysis points to the suspect. See our article on electricity theft detection for the details.
Water loss work is usually the first link in a wider programme. For lighting, parking and waste, see our article on smart city applications; for the organisational side, see digital transformation in municipalities.
Where should a water loss programme start?
The first step of a water loss programme needs no new investment. Gather twelve months of production and billed consumption data, an approximate count of customers and meters, and any zone inlet measurement points you already have. Then get in touch through our contact page; we will interpret your water balance together and plan how to run a pilot in the zone where losses are highest.