This paper aims to demonstrate that through the practical application of advanced methodologies, a significant improvement in the efficiency of distribution systems is not only feasible, but can also provide an example to encourage other utilities to improve their performance. This paper suggests a procedure in which the IWA terminology, the results of field and lab tests, and statistical analysis of meter performance data can be considered jointly with the analysis of demand profiles and numerical models in order to investigate possible mitigation measures for the reduction of apparent losses. The analysis starts from the assessment of potential impact of apparent losses and then, by means of a numerical model, the priorities in the substitution of water meters are suggested. The methodology has been successfully applied to an Italian case study. In addition, the UFR (unmeasured flow reducer) - a device that causes water to go through the meter in batches at flows below the minimum accurately measured flow – has been comprehensively tested in the field. Unrecorded consumption at low flow rates can be evaluated and financial benefits of UFR installation calculated, as part of meter replacement investment strategy.