WQNetXL is a system tool for water quality analyses of water distribution networks (WDNs). WQNetXL is a collection of MS-Excel add-ins. The user-friendly environment allows just in time research transfer to students and technicians, sometimes anticipating research publications. Being water quality analyses based on network hydraulics, WQNetXL embeds the recent advances in hydraulic analyses already implemented in WDNetXL (the system tool for analysis, planning and management of WDNs). Thus, WQNetXL performs water quality also using the advances related to modelling of e.g.: background leakages; pressure-deficient conditions; pressure/flow controlled devices; private tanks; multi-floor orifices; etc.