Few studies in the literature integrate rainwater harvesting and firefighting. Thus, the general objective of this paper was to evaluate the potential use of rainwater as a source of water for firefighting. To do so, two approaches were proposed for the assessment. The first approach was the analysis of the existing literature. Two databases were evaluated as references in engineering fields, of which 32 articles mentioned rainwater as an alternative for firefighting. The main result of the review was the scarcity of articles in the area under study, with some of the existing articles focusing on forest fires. In contrast, others analysed the use of rainwater within the scope of buildings or fire stations. The second approach involved a case study that started by analysing the fire statistics provided by the Military Fire Department of the state of Santa Catarina, Brazil. It was observed that, between 2017 and 2020, building fires represented 25 % of the state's fires and 50 % of the water consumption in firefighting, while the rest of the fire occurrences represented the other half of water consumption. Rainwater can be used not only to reduce the total consumption of potable water but also as a logistics tool towards better response time in the event of a fire. With the firefighting water demand obtained, a Life Cycle Assessment (LCA) approach was performed to assess the potential environmental optimisation in a simplified scope. It was performed in a cradle-to-gate approach, leaving the potential optimisations in transport and logistics apart. Also, a cost assessment was carried out, obtaining a much lower cost for firefighting and providing financial savings for fire stations. As a result, rainwater is expected to decrease environmental impacts, help logistics in fire and save money for fire supression.