For total human needs like toilet flushing, washing, cleaning, cooking, and drinking you need at least several gallons a day.
Add to that industrial needs, then add agriculture.
Saudi Arabia with dirt cheap energy has large scale desalinization but it is not enough. They have a small population. Iceburgs are being towed by several countries for water.
https://www.independent.co.uk/news/...tica-towed-united-arab-emirates-a7715561.html
All things come down to energy.
https://en.wikipedia.org/wiki/Water_supply_and_sanitation_in_Saudi_Arabia
Water supply and sanitation in Saudi Arabia is characterized by challenges and achievements. One of the main challenges is water scarcity. In order to overcome water scarcity, substantial investments have been undertaken in seawater desalination, water distribution, sewerage and wastewater treatment. Today about 50% of drinking water comes from desalination, 40% from the mining of non-renewable groundwater and only 10% from surface water in the mountainous southwest of the country. The capital Riyadh, located in the heart of the country, is supplied with desalinated water pumped from the Persian Gulf over a distance of 467 km. Water is provided almost for free to residential users. Despite improvements, service quality remains poor, for example in terms of continuity of supply. Another challenge is weak institutional capacity and governance, reflecting general characteristics of the public sector in Saudi Arabia. Among the achievements is a significant increase in desalination, and in access to water, the expansion of wastewater treatment, as well as the use of treated effluent for the irrigation of urban green spaces, and for agriculture.
Since 2000, the government has increasingly relied on the private sector to operate water and sanitation infrastructure, beginning with desalination and wastewater treatment plants. Since the creation of the National Water Company (NWC) in 2008, the operation of urban water distribution systems in the four largest cities has gradually been delegated to private companies as well. The apparent paradox of very low water tariffs and water privatization is explained by government subsidies. The government buys desalinated water from private operators at high prices and resells the bulk water for free. Likewise, the government directly pays private operators that run the water distribution and sewer systems of large cities under management contracts. Furthermore, it fully subsidizes investments in water distribution and sewers. Water utilities are expected to recover an increasing share of their costs from the sale of treated effluent to industries. In January 2016 water and sewer tariffs were increased for the first time in more than a decade, which resulted in discontent and in the sacking of the Minister of Water and Energy Abdullah Al-Hussayen in April 2016.[3]
Desalination[edit]
Saudi Arabia is the largest producer of desalinated water in the world. In 2011 the volume of water supplied by the country's 27 desalination plants at 17 locations was 3.3 million m3/day (1.2 billion m3/year). 6 plants are located on the East Coast and 21 plants on the Red Sea Coast. 12 plants use multi-stage flash distillation (MSF) and 7 plants use multi-effect distillation (MED). Both MSF and MED plants are integrated with power plants (dual-purpose plants), using steam from the power plants as a source of energy. 8 plants are single-purpose plants that use reverse osmosis (RO) technology and power from the grid. By far the largest plant in 2012, Jubail II on the East Coast, is a MSF plant built in subsequent stages since 1983 with a capacity of almost 950,000 m3/day that supplies Riyadh. The largest RO plant in 2012 was located in Yanbu on the Red Sea. It supplies the city of Medina and has a capacity of 128,000 m3/day. The MED plants are much smaller. Mecca receives its water from plants in Jeddah and Shoaiba, just south of Jeddah.[15] Ras al Khair, the largest plant of the country with a capacity of 1 million m3/day was opened in 2014, using RO technology.
Saudi Arabia holds approximately 35% of the Arab Region’s desalination capacity which includes Algeria, Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Libya, Mauretania, Morocco, Oman, Palestine, Qatar, Sudan, Syria, Tunisia, the United Arab Emirates, and Yemen.
Furthermore, water desalination requires immense amount of energy, 25% of Saudi Arabia’s oil and gas production is directed towards cogeneration power desalination plants (CPDPs) to generate electricity and produce water. It is estimated by 2030, 50% of Saudi Arabia’s local oil and gas will solely be used to meet the rapidly growing demand for water.[16][17]
Solar desalination. The first contract for a large solar-powered desalination plant in Saudi Arabia was awarded in January 2015 to a consortium consisting of Abengoa from Spain and Advanced Water Technology (AWT), the commercial arm of the King Abdulaziz City for Science and Technology (KACST). The $130 million reverse osmosis plant, co-located with a photovoltaic plant in Al Khafji near the Kuwaiti border, was planned to have a capacity of 60,000 m3/day.[18] The plant would rely on grid power at night and its operator expected to sell electricity to the grid in the future. However, Abengoa filed for bankruptcy at the end of 2015, putting the future of the plant in jeopardy.
Once the first plant is commissioned, a plant ten times larger is due to be built at a hitherto undisclosed location. Both plants are part of a national plan, launched in 2010 and called the King Abdullah Initiative for Solar Water Desalination, to massively expand solar desalination.[19]
Floating desalination. Desalination barges have operated since 2008 to meet high seasonal demand for potable water along the Red Sea coast of the Kingdom. In 2010 the largest floating desalination plant in the world, with a production capacity of 25,000 m3/day (9 million m3/year), was launched on a barge in Yanbu. It is sufficient to supply a city with more than 100,000 inhabitants with drinking water.[20]
