The use of water distribution network models depends highly on the confidence that the operators have on them. Models generated automatically from the Geographical Information System using the hydraulic equations integrated in a simulation model [7] are available in most of the water utilities. Once the first simulation results are compared with the available measurements, calibration is required [6]. This paper presents the process of adjusting the original network model of a village called Sant Joan de Vilatorrada network to fit the simulation results with the measurements. The adjustments in the model range from the macroalibration level to the microcalibration level [3]. The macrocalibration process is based on the analysis done by the engineers, and the conclusions are formalised for future use in other networks. Microcalibration is centred in setting the emitter coefficients using Genetic Algorithm optimisation. The results of the work include an adjusted model for decision taking, an assessment of the background leakage and a methodology to be applied in other parts of the network.