Sustainable approaches to water management require broad community acceptance of changes in policy, practice and technology, which in turn, requires an engaged community. A critical first step in building an engaged community is to identify community knowledge about water management, an issue rarely examined in research. To address this, we surveyed a representative sample of Australian adults (n = 5172). Knowledge was assessed using 15 questions about impact of household activities on waterways, the urban water cycle, and water management. This survey also examined demographics, psychosocial characteristics, exposure to water-related information, and water-related behaviors and policy support. Participants correctly answered a mean of 8.0 questions (Range 0โ15). Most respondents knew that household actions can reduce water use and influence waterway health, whereas less than one third correctly identified that domestic wastewater is treated prior to entering waterways, urban stormwater is not treated, and that these are carried via different pipes. Higher water knowledge was associated with older age, higher education and living in non-urban areas. Poorer water knowledge was associated with speaking a language other than English in the home. Garden size, experience of water restrictions, satisfaction, waterway use for swimming, and certain information sources were also associated with knowledge. Greater water knowledge was associated with adoption of water-saving and pollution-reduction behaviors, and support for both alternative water sources and raingardens. These findings confirm the importance of community knowledge, and identify potential subgroups who may require additional targeting to build knowledge and support for water management initiatives. [ABSTRACT FROM AUTHOR]