The paper aims to understand how the public perceives river water quality and related risks and behaviour. Using the stratified semi-purposive sampling process, the study explores the perception of people residing along the river Yamuna in India. The method applied involved a structured questionnaire survey of 2706 respondents and four focused group discussions with people residing within two kilometres of the river bank. Non-parametric tests such as Kruskal Wallis, Mann Whitney U-test and One-Sample Wilcoxon Signed-Rank Test were used to analyse the data. The findings suggest that the majority of the respondents formulate their perceptions using non-scientific methods like sensorial and heuristics. Perception on sources of pollution is shaped by personal experiences and people do not perceive diffused sources of pollution that affect river water quality. Respondents attributed the pollution in the river to anthropogenic activities and their risk perception was found to be linked to their direct dependence on the river for their daily needs. The paper suggests behavioural change strategies to focus on social, governance, and technological drivers.