Waterwatch is a national water quality monitoring program that engages with the community to raise awareness, educate, monitor, restore and protect waterways. As part of Waterwatch monitoring, local catchment groups, Landcare groups, local residents, schools and landowners are regularly involved in the monitoring of local creeks, wetlands, lakes, rivers and stormwater drains.  Waterwatch data have been traditionally criticised as being of inferior quality compared with professionally collected data and as such have seen limited use and incorporation in state wide data sets. Water quality data collected from 2003 onwards by Waterwatch volunteers in the ACT region were compared with equivalent data collected by government agencies, consulting firms and academic institutions (professionally collected data). The water quality variables compared at river/creek sites were electrical conductivity, pH, turbidity and dissolved oxygen. Some comparisons of total phosphorus data were made, but there was insufficient matching of total nitrogen data available to facilitate meaningful comparison. Good correlations between Waterwatch and professionally collected data sets were observed for electrical conductivity, pH and dissolved oxygen indicating that the quality of these Waterwatch data are indistinguishable from professionally collected data. Weaker and more variable correlations were observed with turbidity and total phosphorus data which are likely caused by method differences and differences in sampling times. While weaker and more variable correlations were observed between the Waterwatch and professionally collected turbidity and total phosphorus data , temporal patterns were consistent for most sites. The quality of the data collected by the community based volunteers provides an opportunity to incorporate Waterwatch programs into jurisdictional wide monitoring strategies with confidence and allows augmentation of existing monitoring effort to enhance water quality management outcomes.