Abstract
All of the possible strategies to reduce water losses in piped distribution systems follow the law of diminishing returns: the higher the expenditure on water loss reduction, the lower the progressive return in terms of water saved. Therefore, water utilities need to estimate the economic level of water losses (ELWL) so that they can reduce their water loss to the level where the cost to reduce the water losses is equal to the value of the water saved. This paper aims to estimate the ELWL using four different methods: the total cost method, the marginal cost method, the cumulative cost–benefit method, and the component-based methods. This analysis is based on data (2011–2016) on the water utilities of the city of Malang (PDAM Kota Malang), Indonesia. It was found that the total cost and marginal cost methods gave almost similar results for ELWL. However, the total cost method is preferred to calculate ELWL because it is the most accurate, easier to apply, and does not need a long data series. In addition, the estimated ELWL for PDAM Kota Malang was 21.76%, which is 3.71% higher than the water loss level estimated in 2016, which means that their strategies to reduce water loss are not cost-efficient. Moreover, the lack of data is a major challenge in the estimation of ELWL in Indonesia. This study emphasizes the importance of estimating the ELWL so that water utilities, especially in Indonesia, can evaluate their strategies in reducing water loss and improving their cost-effectiveness.
Highlights
IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
The cumulative cost and benefits method gives good results in South Korean cases [15], but not in our case. This could be because Perusahaan Daerah Air Minum (PDAM) Kota Malang spent too much money to reduce the water loss, such that the cumulative cost is far higher than the cumulative benefit
We found that the length of the data series will determine the accuracy of the results obtained from three of the methods
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Increasing water-use efficiency by 2030 is part of Sustainable Development Goal 6.4 [1]. This issue will become more important in the future, as the water demand is growing significantly, while water availability is shrinking, the cost of water treatment is increasing and water supply infrastructures are deteriorating [2]. In the upcoming 50 years, the global water demand is predicted to rise by 400% in several sectors [3]. Many countries are expected to face water scarcity [4]
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