This paper summarises the three-waters network (water, wastewater, storm water) model calibration and validation work undertaken in Christchurch after the devastating 2010–2011 earthquakes. The paper outlines some unusual and unique challenges during model calibration due to continual earthquakes in the region and the post-earthquake rebuild work. In case of water supply network model, the validation peak summer date was chosen carefully so that earthquake-related damage and associated rebuild works would have minimal impact on the captured data. The wastewater network was damaged significantly due to the earthquakes. Wastewater flow data were influenced by earthquake damage and post-earthquake major construction activities. Christchurch’s storm water network faced a number of changes – changes in topography, ground levels, river channels and liquefaction – due to the earthquakes. Ongoing model maintenance and updating was a big challenge during model calibration, and an effective collaboration among various teams – GIS, construction contractors, network operations and survey – was important for data collection, data interpretation, model calibration and validation work.