Too often, data regarding water consumption patterns of the users and the results from the meters metrological tests are stored in databases designed for other purposes. This way, calculations about the real performance of the meters are not easy or even possible. Furthermore, engineers have many different methods to obtain the real performance of the meters, being some of them not adequate. A software tool, Woltmann, specially designed to improve water meter management has been developed at the ITA in Valencia. One of the main features of the software is the standardization in the weighted error calculation that it provides. A free Lite version of it will be soon available for download which will help in making unbiased comparisons regarding apparent losses between different water companies.