In evaluation and appraisal criteria used to account for water service leaks was defined pursuant to MD 99/97, criteria that will be applied for the first time in 2012 during the reporting of the 2011 figures. 2012 will see the conclusion of the evaluations related to the possibility, on the basis of available network topological and hydraulic data, of applying the IWA methodology, with particular reference to the calculation of concise leakage indicators, to a series of water network infrastructures, interconnected in various ways and provincial in size, highlighting their potential, limits and critical features.