Dissertation (MSc Natural Resources Management)This study aimed at assessing reliability of Rainwater Harvesting as a Strategy to Alleviate Water Scarcity using Monduli District as a case study. The study was governed by three specific objectives namely; to determine how rain water harvesting was being done and managed by community members, assessing the quality of Rain Water harvested by analysing bacteriological parameters (faecal coliform) and lastly, to determine challenges faced by community on Rain Water Harvesting, and how the community addresses such challenges in Monduli district. The study used Ecological Modernisation (EM) and Diffusion of Innovation (DI) theories as a framework of ideas proposed by Kuhn (1996). The EMT grasps the inherent suggestion that the society will “go green”, given the choice and motivation. It gives six hypotheses as (systemic) structural moderators of household adoption of rainwater harvesting schemes: Consumption and Regime, Commercial Impact, Environmental Impact, Governance and By-law, Societal Stimulus and Technology and Invention and the DI theory offers to deliver the ‘household experience’ through its actor-based approach. The link is constructive: the larger the relative advantage professed in a RWH system, the more probable is adoption The research involved 119 respondents including 23 key informants while data collection was accomplished through key informants’ interview, household questionnaire survey, non-participant observation and laboratory analysis of water sampled from rain water harvested storage. The data collected were analysed using IBM SPSS Statistics V.25.The findings of the study show that, most of the people in Monduli are experiencing water scarcity. The two most common ways identified are rooftop and surface runoff Rain Water Harvesting however; these ways do not meet the requirement of the people as the result, they continue experiencing water scarcity. Also results of faecal coliform of the stored Rain Water indicated that Peter Sironga storage tank was 136.67 Cfu/100ml, Lembris ground reservoir was 1766.67 Cfu/100ml, Meng’oriki ground reservoir was273.33 Cfu/100ml, and Raphael Singano storage tank was 20 Cfu/100ml, Tubanane ground reservoir 1209 Cfu/100ml, Lerunya ground reservoir 3217 Cfu/100ml, Barabarani ground reservoir3023 Cfu/100ml, Zacharia Storage tank 110 Cfu/100ml, Bahati Gasper Storage 12 Cfu/100ml. Generally, faecal coliform for all water samples was above 0Cfu/100ml in relation to Tanzania standard for excellent quality of drinking water. Therefore, to mitigate the problem it is suggested