Optimising Water in Cities: Policies and Technologies for Combating Urban Water Security Global Governance Project Will Rankin  A brief examination of water—stressed cities across the world reveals a growing list of cities of all sizes that are facing water issues, from South America to China. Cities are increasingly facing water stress due to a combination of environmental, demographic, and infrastructural factors. Rising global temperatures and changing precipitation patterns are exacerbating droughts and reducing freshwater availability. Cities in arid and semi-arid regions are particularly vulnerable, as prolonged dry periods strain limited water resources. Meanwhile, the global urban population is growing rapidly, with millions moving to cities annually. This surge in population increases demand for water for domestic, industrial, and agricultural use, often outpacing the supply capacity of existing infrastructure. Poor planning and inefficient water use are further compounding the problem. Many cities rely heavily on a single water source, leaving them vulnerable to shortages. Additionally, aging infrastructure results in significant water losses through leaks. Pollution of rivers, lakes, and groundwater by industrial waste, agricultural runoff, and untreated sewage is further exacerbating the global water shortage problem, reducing the amount of clean water available in our cities. Over-extraction of groundwater for urban needs further depletes this critical resource, often faster than it can be replenished. Water stress is also worsened by uneven distribution and access, often meaning marginalised communities bearing the brunt of shortages. Addressing water stress requires sustainable planning, investment in resilient infrastructure, and global cooperation to adapt to changing climatic realities.

Policies and technologies......Urban areas worldwide are increasingly adopting innovative policies and technologies to combat water scarcity, with a renewed sense of urgency. Newspaper headlines share terrifying prospects of extreme water shortages, causing city authorities and federal departments to take decisive action. For instance, Cyprus plans to enhance its reliance on desalination plants due to a series of arid winters that have significantly reduced dam water levels. The government aims to implement four additional mobile desalination units by October 2025, each providing 30,000 cubic meters of potable water daily, to address immediate shortages and ensure long-term water security. In the United States, the northeastern region is experiencing historically dry conditions, prompting experts to advocate for major changes in water management. Proposed solutions include replenishing groundwater through permeable surfaces and injecting treated wastewater, encouraging water conservation via incentives, and reusing water for non-potable purposes like flushing toilets and cooling buildings. These measures aim to mitigate future water shortages exacerbated by climate change. Similarly, California is facing significant challenges to its water supply due to prolonged droughts. In response, efforts are underway to develop and implement on-site water reuse systems — water recycling — to conserve and diversify water resources. San Francisco’s Public Utilities Commission launched the Onsite Water Reuse Program in 2012 to facilitate this initiative. The programme has led to the development of permitting processes for private sectors to adopt these systems. With the goal of making water recycling more accessible and efficient, Silicon Valley startups like Epic Cleantec have emerged, offering solutions for large buildings and integrating energy-saving mechanisms.

These systems not only address water scarcity but also provide economic benefits to developers. However, retrofitting existing buildings remains a challenge due to infrastructure constraints. California’s agriculture sector, a heavy user of water, also benefits from recycled water, crucial for crop irrigation.Public awareness campaigns and legislative support have been essential in promoting water conservation and the safe use of recycled water. These efforts are paving the way for stronger water infrastructure and sustainable water management in California.

Singapore.....Singapore, the densely populated city-state in Southeast Asia, has historically grappled with significant water scarcity challenges due to limited natural freshwater resources and a growing urban population. It has imposed water rationing since the 1960s, but continues to face water stress, especially in light of the fact that it has no natural freshwater sources of its own. Even so, Singapore is successfully meeting the increasing water needs of its rapidly growing population and economy. To address its water issues, Singapore has developed a comprehensive and innovative water management strategy known as the “Four National Taps,” which includes local catchment water, imported water, NE water (reclaimed water) and desalinated water.......read on  https://www.globalgovernanceproject.org/optimising-water-in-cities-policies-and-technologies-for-combating-urban-water-security/will-rankin/

AND......Iran’s Capital Must Relocate Due to Dire Water Situation, President Insists. Tehran’s troubles are a red flag for thirsty cities around the globe.  Mother Jones Shayna Korol November 22, 2025  Originally published by Vox and is reproduced here as part of the Climate Desk collaboration.Rationing has between midnight and 5 am. The entire country is in an unprecedented drought, and has received no rain at all since the start of September, and no rainfall is expected for the foreseeable future.The city depends on five major reservoirs for its water supply. One has dried up completely, with another below 8 percent capacity. The managing director of the Tehran Regional Water Authority told state media last week that the Karaj Dam has only two weeks of drinking water left. The drought extends beyond the city, too. The water reserves of Mashhad, the second largest city in the country, have dropped below 3 percent capacity, putting 4 million people at imminent risk. But if nothing changes, Tehran may soon face a drought or when a municipality can no longer supply drinking water to its residents and taps run dry. In October, President Masoud Pezeshkianclaimed that Tehran could no longer serve as the country’s capital, citing the water crisis as a major factor. ”If it doesn’t rain in Tehran by late November, we’ll have to [formally] ration water,”Pezeshkian told Iranian state media on Thursday. “And if it still doesn’t rain, we’ll have to evacuate Tehran.” (Update: On Thursday, Pezeshkian president again said the capital will need to be moved.)

While it’s unlikely evacuation will happen any time soon, Tehran’s water crisis is not made equal. When the taps run dry, more affluent Tehranis purchase mineral water or rely on water tankers, a prohibitively expensive option for many. The rest must rely on charity, or they will die of thirst. Water use in Tehran is quite high, even for cities. But Iran’s water problems go deeper than this record-breaking drought. The country is uniquely isolated and subject to numerous sanctions, crippling the economy and making it very difficult for Iran to obtain state-of-the-art water technologies. It’s an enemy state to many of its neighbors, as well as regional leaders in desalination technologySaudi Arabia, and theUnited Arab Emirates. But desalination is t in an Iranian context, often coming at a water mafia”—a shadowy and well-connected network driving these megaprojects for their own gain. “Iran faces water bankruptcy, with demand far outstripping supply,” Kowsar wrote in Time. “The collapse of water security in Iran has been decades in the making and is rooted in a mania for megaprojects—dam building, deep wells, and water transfer schemes—that ignored the fundamentals of hydrology and ecological balance.”

Iran is also particularly vulnerable to the effects of climate change: Over 82 percent of the country is arid or semi-arid, and Iran is sixth on the list of countries most prone to natural disasters. The country grows thirsty crops, and its quest for food security and self-sufficiency is a tremendous driver of its water bankruptcy. The agricultural sector comprises up to 90 percent of the country’s total water withdrawals. But Iran’s environmental crisis does strain existing geopolitical tensions both inside and outside of the country. Water is sometimes transported from one region of the country to supply another, driving fears that certain ethnic populations are intentionally being deprived at the expense of others. Yale University historian and Iran expertArash Azizi, who is also a contributing writer for The Atlantic, told me that despite the tremendous humanitarian cost of continued sanctions, they are very unlikely to be removed in response to the water crisis. 

Tehran is running out of water. Rationing has begun in Iran’s capital city, with some of the approximately 10 million residents experiencing nightly pressure cuts” between midnight and 5 am. The entire country is in an unprecedented drought, facing its driest—and hottest—autumn in nearly 60 years. Tehran has received no rain at all since the start of September, and no rainfall is expected for the foreseeable future. The city depends on five major reservoirs for its water supply. One has dried up completely, with another below 8 percent capacity. The managing director of the Tehran Regional Water Authority told state media last week that the Karaj Dam has only two weeks of drinking water left. The drought extends beyond the city, too. The water reserves of Mashhad, the second largest city in the country, have dropped below 3 percent capacity, putting 4 million people at imminent risk. But if nothing changes, Tehran may soon face Day Zero—or when a municipality can no longer supply drinking water to its residents and taps run dry. In October, President Masoud claimed that Tehran could no longer serve as the country’s capital, citing the water crisis as a major factor. ”If it doesn’t rain in Tehran by late November, we’ll have to [formally] ration water,” Pezeshkian told Iranian state media on Thursday. “And if it still doesn’t rain, we’ll have to evacuate. Update: On Thursday, Pezeshkian president again said the capital will need be moved.) While it’s unlikely evacuation will happen any time soon, Tehran’s water crisis is not made equal. When the taps run dry, more affluent Tehranispurchase mineral water or rely on water tankers, a prohibitively expensive option for many. The rest must rely on charity, or they will die of thirst.

Water use in Tehran is quite high, even for cities. But Iran’s water problems go deeper than this record-breaking drought.The country is uniquely isolated and subject to numerous sanctions, crippling the economy and making it very difficult for Iran to obtain state-of-the-art water technologies. It’s an enemy state to many of its neighbors, as well as regional leaders in desalination technology—Israel,Saudi Arabia, and theUnited Arab Emirates. But desalination is largely irrelevant in an Iranian context, often coming at a high environmental cost. According to water issues analyst Nik Kowser, Iranians are under the thumb of a >water mafia”—a shadowy and well-connected network driving these megaprojects for their own gain. “Iran faces water bankruptcy, with demand far outstripping supply,” Kowsar wrote in Time. “The collapse of water security in Iran has been decades in the making and is rooted in a mania for megaprojects—dam building, deep wells, and water transfer schemes—that ignored the fundamentals of hydrology and ecological balance.”.......read on   https://www.motherjones.com/environment/2025/11/tehran-iran-water-shortage-rationing-evacuation-desalinization-drought-middle-east/