There is growing realisation among environmental and social studies researchers that people's decision‐making about water use conforms to their internal norms and beliefs, which are developed in social and cultural contexts. Little research, however, has addressed the possible impacts that ethnic and cultural diversity may have on domestic water use and management. This paper presents the results of a study conducted in Sydney, with specific reference to questionnaire findings. Among respondents from different ethnic and cultural backgrounds, significant differences were observed in terms of perceptions, specific knowledge, attitudes, and self‐reported behaviours in relation to water use and conservation. The disparities identified were not masking socio‐demographic and economic characteristics but were the result of a series of constructs closely tied to ethnicity, including cultural value, environmental experience, language preference, and information access. As a factor explaining variation in the engagement of pro‐conservation behaviour, ethnic status was found to be more useful than some socio‐economic factors. The study highlights the importance of including ethnicity and cultural sensitivity issues in the decision‐making process of environmental management.