This paper quantifies some of the economic benefits that a culture of rainwater harvesting could produce in the case of Bogota. The study makes projections of future water needs until 2035, based on local economy and population growth as determining variables of water service needs. It also discusses the appropriateness of promoting water harvesting as a strategy to manage the urgent situation caused by the limitations that climate change would provoke on the water supply of the city. Projected water supply needs for the growing population evidence the need of an increase of 37.6% in the supply capacity of drinking water for the localities that make up the urban area of Bogota. The article concludes that rainwater harvesting would generate significant savings in water and water supply costs for users and for the State.