The use of rainwater harvesting by private citizens can be a valuable practice that can mitigate problems such as urban flooding and other possible effects of global warming. In this study, the citizen rainwater harvesting experience was examined. The relationship between citizens’ participation awareness and their lifestyle were analyzed to elucidate their needs and goals. Furthermore, this study discusses the factors that lead to citizen participation in rainwater harvesting activity. To grasp the citizens’ participation consciousness of rainwater harvesting, we used an internet questionnaire to conduct a survey that targeted citizens nationwide in August of 2017 (n = 1800). As the results, citizens’ participation awareness depending on the lifestyle, such as young people are highly conscious about participation than elderly layer, and the type of residence affects the participation awareness of citizens. Rainwater harvesting experience affects the participation awareness as well. Benefits on recreation such as communication and refresh, ease of maintenance work lead to continuation of rainwater harvesting. The results also elucidated that citizens are concerning with the merits of stabilization of the local environment such as disaster prevention and habitat, mitigation oh the heat island phenomenon, not the merits of individual recreation.