Water is one of the vital natural resource supporting human health, economic development and ecologicaldiversity. Many parts of Karnataka have continued to experience drought conditions with an alarming consistency. Therivers are getting contaminated and drying up, while underground water table is shrinking swiftly. The municipality watersupply system meets only a part of the household requirement while the remaining part is addressed by water from borewells or purchased from uncertain sources. In this concern Roof-top rainwater harvesting (RRWH) has proven to be costeffective technology in mitigating water scarcity. Rainwater is the purest form of water and is a boon for arid and semi-aridregions, if harvested accurately then it can eliminate problems of water scarcity and droughts. Hubballi-Dharwad MunicipalCorporation (HDMC) has provided corporation water facility to all the residential areas yet people face acute waterscarcity problems which increases in summer season. Hence, to solve water scarcity they made adoption of RRWHmandatory for all residential and commercial buildings constructed in Dharwad and Hubballi cities. This study wasconducted in order to analyze the reason for adoption and utilization for RRWH systemin some selected areas of Dharwadand Hubballi cities. The results of the study revealed that majority of the people adopted the system because of drying upof surface and ground water resources. They utilized the harvested rainwater for recharging their bore wells, while only fivehouses used it for drinking. Majority of the non-adopters did not adopt it because of insufficiency for their use. But showedinterest to adopt if they were granted a subsidy or concession in their monthly water bills. This study concludes that alongwith compulsion for adoption of RRWH public should also be thoroughly educated about this sustainable self-relianttechnology for encouraging adoption and utilization.