Updated: Jul 5, 2019
The increase in population, civilization, farming and industrialization has made water, probably the most precious utility being used domestically as well as for industrial purpose. Till 1990s, reliable and standardized methods for accounting water losses were missing. As the demand for water increased steeply, organisations around the world started formulating tools and methodologies to identify water losses and effectively manage them.
Non-Revenue Water or more popularly known as 'NRW' or Un-accounted for Water (UFW) is one such globally accepted indicator for determining the efficacy of water networks. As the name suggests, NRW is difference between total water put in the distribution system and amount of water which is actually billed to the consumers.
Though NRW can be defined very easily, actually finding out NRW for water networks could be quite a difficult task. To put it even more simply, NRW is sum of all the water which is lost in the network and not billed. Usually, NRW has three major components:
Physical Losses : Physical losses are direct consequence of poor operation and maintenance of water networks. For instance, unattended leakages in the pipes will lead to wastage of considerable amount of water which will ultimately be not billed. Detecting problems in underground infrastructure and getting it fixed, is even more difficult. Losses from all such ill maintained assets will contribute to the physical losses.
Commercial Losses : Compared to physical losses, commercial losses are more difficult to trace and rectify. Faulty or tampered meters, directly stealing water by taking unauthorized connections from the pipes, faults or deliberate errors, while taking meter readings will result in some amount of water being used by the consumer but not accounted and billed. The sum of all such losses is termed as commercial losses.
Un-billed Authorized Consumption : In large networks, certain users are authorized to consume water without it being billed. For instance, water used by government hospitals or for firefighting during an emergency would not be billed to any particular user.
When the above three losses are added, one will arrive at the correct quantum of NRW for a particular water utility.
The graphic below gives clear break of NRW and its various components:
Why Should One Worry about NRW?
More than USD 14 billion are lost every year by water utilities around the world and more than a third of it is lost by utilities in developing countries. (Source: Bill Kingdom, et. al., Water Supply and Sanitation Sector Board Discussion Paper Series, Paper No.8, December 2006)
Issues and Challenges with documenting and reducing NRW:
Minimizing NRW is a tough and challenging task. Few of the challenges are briefly explained below:
Lack of factual data: To calculate the quantity of NRW, proper track of a large number of parameters has to be maintained. Some of these parameters are average water supply time, pressure at the consumer end, total number of connections etc. Many utility companies do not have this data. Tracking NRW becomes very difficult in such cases.
Absence of Water Balance Record: In order to reduce NRW, it is essential to determine the breakup of commercial losses and physical losses. Water balance record is available with very few utility companies which makes minimizing NRW very challenging.
Losses in Water Networks: As many studies across the globe indicate, up keeping the water networks is a tough task, at which most of the utility companies fail. As a result, the water losses in distribution network itself are alarmingly high.
Absence of District Metered Areas: Absence of DMAs lead to inefficient water flow management which poses severe challenges on NRW reduction. Read more about DMAs here.
Because of all these challenges, the data available about NRW is not only far from reality, but also misleading at times.
How bringing down NRW helps utility managers as well as consumers?
Reduced NRW will significantly bring down the need of fresh water, as available water will be distributed much more efficiently. As a result, even the load on water treatment units and pumping units will be reduced. This will also lead to reduced energy costs and operation & maintenance costs.
Reducing NRW increases the revenue and profitability of the water utility. Increased revenue leads in better maintenance of the water infrastructure, which further increases the quality of water and the efficiency at which it is distributed. As the NRW goes down, water utilities become more transparent and the understanding of consumption patterns i.e. demand becomes more comprehensive, increasing the responsiveness of water utilities.
The understanding of actual demand also facilitates correct estimation of usage trends and predictions.
How to Minimize NRW?
Numerous technological advancements in the fields of hydraulic modelling and metering can be effectively used to bring down NRW. Here is a list of a few of them:
Hydraulic Modelling: Hydraulic modelling can be very effectively used to plan, model and design water networks intelligently, so that some of the NRW can be controlled in the early stages itself. For instance, designing maintenance friendly water networks will facilitate periodic maintenance which will ultimately help mitigating losses through the leakages. This is done using criticality studies on the hydraulic model to understand the optimal locations of valves on the network, for better control and management.
Adoption of DMA approach: DMAs are small isolated clusters of water users. Water coming in and out of each DMA is monitored. While addressing a complex issue like NRW, following DMA level approach is more realistic and actionable. DMA level solutions can be much easily implemented and monitored also than city level efforts. Read more about DMAs here.
Smart Metering: As the common saying goes, 'we cannot improve what we do not measure'. Metering is a very simply yet very effective way of monitoring water usage and find out the gaps. Water metering could actually be the first step in the process of NRW reduction.
Effective slum policy: Most of the times, slums comprise of dense population of users and tracking the authenticity of individual users becomes very difficult. De-linking water connection with land ownership, giving individual connections as against free public water posts, waiving off subsidy after a certain quantity of usage can help in reducing NRW on account of slums or densely packed user groups.
Use of GIS: Migration to GIS can work wonders by providing many insights into the water usage, which can be used to bring down NRW. For instance, GIS can allow for area wise staggered billing which can be very helpful for NRW monitoring. GIS will also help identify unauthorized connections.
Use of IoT: Harnessing the power of Internet of Things (IoT) can help us in many ways right from detecting sensor failure to getting access to real time data. Customized IoT solutions can lead to rapid detection of leaks and breakdowns, detection of fraud/ theft etc. Gaining access to this data will allow for bringing down NRW effectively.
From the above discussion, it is quite clear that advanced technology can prove to be one of the important factors in identification of NRW and then bringing it down. A change like this can happen from top to bottom and hence, strong willingness and commitment at the policy makers' side is warranted.
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