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This article is part of our publication ‘Reducing urban water loss’.
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Non-revenue water
Planning and prioritising NRW reducing initiatives
Securing the right level and quality of information for a successful NRW reduction programme.
3 March 2021
Water utilities with low quality installations, poorly maintained infrastructure and no leakage management systems in place easily lose up to 50 per cent of the water produced. To reverse this development, the first step should be to conduct a water audit based on all available data and develop an NRW master plan for upcoming investment plans and their projected returns.
It is crucial that an NRW reduction programme is managed and understood from the highest level of the organisation to the lowest. NRW reduction must be an agreed strategy for the entire organisation, based on a holistic NRW master plan. The first step is to conduct a water audit that includes
an assessment and analysis of the performance of the water distribution system as well as identifies and quantifies areas for improvements. The outcome of the water audit is then used as essential input into the NRW master plan that will serve as the basis for upcoming expansions, rehabilitations and investment plans as well as their projected returns.
With respect to NRW reductions, the most important outcomes of the water audit are:
- The IWA water balance, including a baseline for the NRW level.
- A component analysis of the IWA water balance that details the relation and magnitude of the elements that make up the total NRW, including dividing thewater losses into real losses and apparent losses. The water audit should be implemented as a recurring (annual) event to continuouslyquantify the effects of the implementation of the NRW master plan on the water balance, and thus enable the utility to add any required modifications or corrective actions to the master plan. Once completed, the NRW master plan will provide the following information:
- A prioritised list of activities and investments to strengthen the NRW reduction programme.
- Calculation of the Economic Level of Leakage (ELL) based on cost-benefit calculations. See the illustration below for reference.
- Mapping of root causes for real losses and apparent losses respectively, with a clear distinction between the substrategy, activities and targets for each.
- Activities developed on the basis of cost-benefit calculations such as active leakage control, district metering, pressure management, meter
replacement etc. - A strategy for the implementation and development of the Information Communication Technology (ICT) systems including GIS, SCADA, modelling tools and management systems.
- Design and implementation of District Metered Areas (DMA) and Pressure Management Areas (PMA) based on hydraulic modelling.
- Budgets for the NRW reduction activities, the financial benefits and specific ROI.
Ensuring the highest return on investments
The key is to identify where the returns on investment will be highest. Economic Level of Leakage (ELL), which is calculated as part of the master plan, will provide the answers. It takes into account cost-benefit analyses relating to each element of NRW, as provided from the water audit. It also takes into
account the forecasted influence of the reduction in NRW on future investments in treatment plants, raw water abstraction, pumping stations etc. as well as the potential effects on revenue generation and energy savings.
Squeeze the box
Standard illustration of potential reduction of real losses through four types of activities; pressure management, speed and quality of repairs, active leakage control and pipeline management and rehabilitation.
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