Aquifers are a major source of water in Saudi Arabia. They are vast underground reservoirs of water. In the 1970s, the government undertook a major effort to locate and map such aquifers and estimate their capacity. As a result, it was able to drill tens of thousands of deep tube wells in the most promising areas for both urban and agricultural use.

Another major source of water is the sea. This is done through desalination, a process that produces potable water from brackish seawater. Saudi Arabia is the world’s largest producer of desalinated water.

The Saline Water Conversion Corporation (SWCC) operates 27 desalination stations that produce more than three million cubic meters a day of potable water. These plants provide more than 70 percent of the water used in cities, as well as a sizeable portion of the needs of industry. They are also a major source of electric power generation.

Dams are used to capture surface water after frequent flash floods. More than 200 dams collect an estimated 16 billion cubic feet of runoff annually in their reservoirs. Some of the largest of these dams are located in the Wadi Jizan, Wadi Fatima, Wadi Bisha and Najran. This water is used primarily for agriculture and is distributed through thousands of miles of irrigation canals and ditches to vast tracts of fertile land that were previously fallow.

An expanding source of water is the use of recycled water. The Kingdom aims to recycle as much as 40 percent of the water used for domestic purposes in urban areas. To this end, recycling plants have been built in Riyadh, Jeddah and other major urban industrial centers. Recycled water is used for irrigation of farm fields and urban parks.