This study set up the revenue water ratio that could be achieved within the range of the expenses of the water distribution network maintenance project, developed an analysis methodology that could estimate the additional project quantity to achieve the target revenue water ratio of 85% and applied and verified that to S. City. This methodology allowed the distribution of the leakage quantity for each leakage component by the pipeline through the total revenue water account balance analysis and BABE approach and the redistribution into the calculated leakage quantity more accurately through a step test. In addition, the level of reduction in leakage and the quantity of the project were estimated before and after the application of four strategies for the promotion of the revenue water ratio presented by IWA, according to the leakage components by the pipeline. As a result of the application of this analysis method to S. City, it would be possible to achieve up to the revenue water ratio of 81.0%, which was 74.7% in the beginning, if the water distribution network maintenance project was promoted within the range of the project expenses, and to achieve the revenue water ratio of 85.0%, the goal of the project, it would be necessary to replace the pipeline of 22.2% of the entire pipelines in the target area. As a result of the re-estimation of the revenue water ratio achievable, applying the actual water distribution network maintenance quantity in the scope of the business with the results of this analysis, the revenue water ratio was 81.7% while the actually measured revenue water ratio was 82.3%. Thus, the reliability of this analysis method could be secured to some extent.

This study describes a reasonable planning method for water meter replacement which can minimize the metering under-registration for an increasement of revenue water. The increment analysis of real water usage was used to establish a replacement plan. The meter replacement database collected from K City was used as the basis of this analysis. The database included 964 connections of domestic and non-domestic consumers that had their meter replaced by aging at 2011.The result showed that the corelation between unregistered water volume and water meter age was lower than commonly expected where the current criteria of replacement is only water meter age(8 years) excluding the meters older than 13 years. And in the analysis result of water usage for 8 years, the total amount and increment of water usage had a significant effect on unregistered water volume. However the relation was different tendency as a total volume and slope of increment. In case of total water volume was larger than 10,000 , larger than 7,000 and increment of 0.0 ~ -0.3, larger than 6,000 and increment more than -0.3 were analysed to need a replacement because of metering under-registration.