Non revenue definition
Non-revenue water (NRW) refers to water produced by utilities that is lost before it reaches the customer. This loss can occur for various reasons, categorized into two main types: real losses and apparent losses. Real losses arise from physical issues such as leaks in the distribution system, while apparent losses stem from theft, metering inaccuracies, or unbilled authorized consumption. High levels of NRW pose significant threats to the financial sustainability of water utilities and compromise water quality. NRW is typically quantified as a percentage of the total water produced, but can also be expressed in terms of volume lost per kilometer of distribution network daily.
Components of Non-Revenue Water
– Breakdown of NRW
The International Water Association (IWA) has established a comprehensive methodology to analyze the components of NRW, which includes:
1.Unbilled Authorized Consumption: Water used for purposes like firefighting or by certain institutions without charge.
2.Apparent Losses: Losses due to theft or inaccuracies in water metering.
3.Real Losses: Water loss from transmission mains, storage facilities, distribution mains, or service connections.
Understanding the specific components of NRW is crucial for utilities to devise effective strategies for reduction. However, many utilities struggle to accurately assess these components, complicating efforts to mitigate NRW. Effective metering at production sites, key distribution points, and consumer locations is essential for estimating NRW levels.
– The Role of Water Audits
Water audits serve as vital tools for assessing NRW. There are two types of audits: validated and unvalidated. Unvalidated audits rely on estimates and can have a high error margin, while validated audits involve rigorous testing and data verification. Unfortunately, many utilities, especially in developing countries, lack validated audits, making it difficult to implement effective reduction strategies. The American Water Works Association (AWWA) has developed software to help utilities assess the validity of their water audit data and guide loss control planning.
Indicators of Non-Revenue Water
The most common metric for measuring NRW is the percentage of water produced that is classified as non-revenue. While this indicator is straightforward, it has limitations when comparing NRW levels across different utilities or tracking changes over time. A more reliable approach involves measuring NRW in terms of absolute losses per connection per day, as recommended by the IWA. The International Benchmarking Network for Water and Sanitation suggests using multiple indicators, such as percentage losses, losses per connection, and losses per kilometer of network, to provide a more comprehensive view.
– Infrastructure Leakage Index (ILI)
The Infrastructure Leakage Index (ILI) has been developed as an alternative metric to assess real losses. The ILI compares Current Annual Real Losses (CARL) to Unavoidable Annual Real Losses (UARL), providing a more nuanced understanding of leakage issues.
Overview of NRW Levels Worldwide
Globally, NRW is a significant issue, with the International Energy Agency estimating that 34% of all water produced becomes non-revenue water. The extent of the problem varies by region:
– United States: NRW losses range from 10% to 30%, with some utilities reporting losses as high as 50%. The federal government estimates that leaks account for 16%, equating to approximately 2.1 trillion gallons of non-revenue water annually.
– Europe: Leaky infrastructure results in an annual loss of about 80 billion euros.
– India: In Delhi, NRW was around 50% in 2005, attributed to inefficiencies and corruption.
– Taiwan: The non-revenue water rate was 27% in 2013, costing approximately NT$2.5 million (US$76,000) daily.
– Malaysia: NRW was reduced from 30.1% in 2008 to 19.3% by 2015 through acknowledgment and targeted interventions.
Benefits of Reducing Non-Revenue Water
Reducing NRW presents numerous advantages, particularly in developing countries where losses are most pronounced. The World Bank estimates that halving NRW levels could save utilities around US$2.9 billion annually and provide water access to an additional 90 million people. Key benefits of NRW reduction include:
– Financial Gains: Increased water sales and reduced production costs can delay the need for costly infrastructure expansions.
– Improved Knowledge: Enhanced understanding of the distribution system leads to better management.
– Enhanced Firefighting Capability: Increased water pressure improves emergency response capabilities.
– Reduced Property Damage: Less leakage translates to fewer damages from water-related incidents.
– Lower Contamination Risks: Better management of water resources reduces the risk of contamination.
Moreover, effective NRW reduction initiatives can foster positive relationships with the public and employees, promoting a culture of water conservation.
Successful Programs for NRW Reduction
Numerous cities worldwide have successfully reduced their NRW levels through various strategies:
– Dolphin Coast, South Africa: Reduced NRW from 30% in 1999 to 16% in 2003.
– Istanbul, Turkey: Dropped from over 50% in 1994 to 34% in 2000.
– Jamshedpur, India: Achieved a reduction from 36% in 2005 to 10% in 2009.
– East Manila, Philippines: Reduced NRW from 63% in 1997 to 16% in 2009.
– Phnom Penh, Cambodia: Decreased from 72% in 1993 to 6% in 2008.
These successes were achieved through long-term commitments from utility management and government support, often requiring at least four years of sustained effort.
Challenges and Pitfalls in Reducing NRW
Despite the potential benefits, many NRW reduction programs fail to meet their objectives. Common pitfalls include:
– Overemphasis on Real Losses: Programs often focus excessively on real losses while neglecting apparent losses, leading to suboptimal outcomes.
– Sustainability Issues: Initial reductions in NRW may not be maintained, as both apparent and real losses tend to increase without ongoing intervention.
– Lack of Comprehensive Strategies: Successful NRW reduction requires changes in management practices, organizational culture, and human resources.
The World Bank identifies several reasons for the ongoing challenges in reducing NRW, including:
– Lack of political support for initiatives that do not yield immediate visible results.
– Engineers’ preference for designing new infrastructure over maintaining existing systems.
– Insufficient dedication from management to invest in long-term solutions.
Conclusion
Non-revenue water represents a significant challenge for water utilities globally, affecting financial viability and water quality. Addressing NRW requires a multifaceted approach that includes accurate measurement, effective auditing, and a commitment to sustainable practices. While successful programs exist, ongoing efforts are needed to overcome the inherent challenges and ensure that water resources are managed efficiently and equitably. By prioritizing NRW reduction, utilities can enhance their operational efficiency, improve public relations, and contribute to broader water conservation efforts.
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Reference
1.Non-revenue water
https://en.m.wikipedia.org/wiki/Non-revenue_water
2.What Is Non-Revenue Water?
https://www.fluencecorp.com/what-is-non-revenue-water/
