... Public authorities must not only ensure proper management and use of resources, but also do it with transparency (GRI, 2005;Midin et al., 2016), so reports are a way for information disclosure. For accountability purposes, information is reported to stakeholders through activity (Araújo and Branco, 2009), budgetary and financial (Carvalho et al., 2007;Mack and Ryan, 2006;Nogueira and Jorge, 2012), social (García-S anchez et al., 2013;Mussari and Monfardini, 2010), environmental (Frost and Seamer, 2002;Lodhia et al., 2012;Lynch, 2010) and sustainability reports (Dumay et al., 2010 andLamprinidi andKubo, 2008 analysed the application of the GRI guidelines and the production of sustainability reports by public entities; Farneti and Guthrie (2009) (2012), also the countries worldwide have been implementing good practice awards to the public sector level (see Borins, 2000;Hartley and Downe, 2007;L€ offler, 2001;Radnor, 2009). In Portugal, some of the good practices awards for PSOs are the "Environmental-Defence Award", a national award attributed to the environmental good practices of the military units and bodies belonging to the Portuguese Armed Forces (Ramos and Melo, 2005); "ECO XXI Award", which aims to distinguish the local government sustainability practices (Nogueiro and Ramos, 2014); "Water and Waste Service Quality Awards", assigned by the sector regulator (ERSAR -Entidade Reguladora dos Serviços de Aguas e Resíduos) and the newspaper Agua&Ambiente, which purpose is to prize the management entities of the sector of Water and Environment that outstanding in the services provided (ERSAR, 2014). ...