Introduction: Rain water harvesting is the process of collecting, storing, and utilizing rainwater that falls on surface like rooftops, land or another catchment area.

Objectives: To assess the level of knowledge in public regarding rain water harvesting as measured using structured knowledge questionnaire. To find the association between knowledge score on rain water harvesting among general public with their selected baseline variables.

Methodology: A descriptive approach was used on this study. This study was conducted in selected communities of Mangaluru. 60 samples were selected by simple random sampling technique. Data was analyzed by using descriptive and inferential statistics.

Results: The findings of the study showed that in the pre-test 33.3% of the sample had good knowledge and majority (56.7%) had average knowledge and 6% of the sample had poor knowledge. Conclusion: Findings of the study showed that there was average knowledge regarding the RWH in the general public of Mangaluru. The SIM will facilitate knowledge regarding the RWH. It is an effective method to provide knowledge to the public.