Rain is the main water resource in Syria, affecting the availability of all other water resources. The average annual rainwater resource is estimated at 46 billion cubic metres (BCM).

Water resources in the UAE can be classified into two main categories: conventional, such as surface water (including aflaj water systems, springs and dams) and groundwater (shallow and deep aquifers), and non-conventional, such as desalinated water, treated wastewater and cloud seeding.