Syria, as well as many other countries in the Middle East, faces serious water shortage problems. Available water per capita (AWPC) will dramatically decrease due to climate change, population increase, and water needed for economic growth. Rainwater harvesting can play an important role in increasing available water in Syria. However, the absence of rainwater sewer systems in many rural areas in Syria necessitates giving a priority to construct collecting systems for future policies and plans. The objective of this paper is to estimate the potential increase in available water from collecting roof rainwater in small reservoirs and using other rainwater harvesting techniques. The potential increase in water availability due to rainwater harvesting could be as much as 35 million m3 of water by roof rainwater harvesting in rural areas. This could be combined with other rainwater harvesting techniques in both urban and rural areas. Rainwater harvesting can be used to irrigate fruit trees that are less sensitive to changes in water quality and that can be especially adapted for passive irrigation techniques.