Access to clean water is in many places taken for granted, just like the fresh air we breathe. We forget that clean water is a product, and that producing enough is actually a comprehensive, detailed process. And resources are scarce. By adding inadequate distribution management, we are faced with a more invisible, yet crucial problem: water loss, also referred to as non-revenue water, or NRW.
What is non-revenue water?
Non-revenue water (NRW) is basically produced, cleaned water which is lost somewhere in the water distribution system, never reaching its final destination. This means water not used or paid for, affecting local economies as well as local resources available.
Non-revenue water is a global challenge
The problem is universal, ranging from NRW levels of about 5 % to as much as 80 % in certain areas.
A World Bank study puts the global estimate of physical water losses at 32 billion cubic meters each year, half of which occurs in developing countries. Could these water losses be halved, it would be enough to supply around 90 million people.
The reasons for water losses are many, ranging from leakages, pipe bursts, and poor water management to illegal connections and unauthorised consumption. But luckily, so are the available solutions - and their benefits.
Leakages and pipe bursts
Leakages cause water loss from the pipe network and occur, among other things, at pipe bursts. This means that cleaned water is lost and never reaches the consumers. Water loss due to leakages therefore affects both the economy of the utilities and the environment by possible nuisances, and it contributes to unnecessary waste of resources. Leakages and pipe bursts can occur suddenly or gradually develop over time due to lack of maintenance, corrosion or wear and tear.
Poor water management
In many parts of the world, poor management of water resources contributes to water loss. This may, for example, be lack of maintenance of the supply network resulting in leakages and pipe bursts, or lack of customer meters, so that the utilities cannot bill the consumers based on actual consumption.
Illegal connections and unauthorised consumption
Unauthorised consumption is for example theft of water or filling of a vacuum tanker from a random fire hydrant not assigned for the purpose.
Managing non-revenue water and reducing water loss through strategic efforts and advanced technologies
Operating a water distribution network is no easy task. A network often covers an extensive area and a complex, hidden system of pipes, making it difficult to detect changes, damages or illegal connections. Managing water losses or non-revenue water in an open system would then also mean working in a reactive, passive manner, where activities are initiated only when a loss becomes visible or is reported.
Dividing the network to allow for pressure management and leakage control
Therefore, dividing the supply network into smaller sections - district metering areas (DMA) - is a more efficient technique; it is then possible to calculate water losses individually, and operators are able to better plan and prioritise their efforts.
Leakages can easily be detected through noise loggers integrated in ground-level surface boxes, enabling operators to set in exactly when and where needed. This secures quick repair, meaning less water lost and a minimum disturbance of the network customers.
By investing in a targeted leak detection program, it is in most places possible to reduce the overall leakage in the distribution system by at least 40–50 %.
By using DMAs, it is also possible to measure and manage the water pressure in the different areas of the water supply network.
Learn more about the advantages of pressure management in the supply network, and how this is helpful in reducing water loss and NRW levels.