Tehran’s Water Crisis: Capital on the Brink of 'Day Zero' — A Warning for Arid Cities

Tehran’s water supply is collapsing

Tehran — home to roughly 10 million people — has begun nightly pressure cuts as reservoirs fall to critically low levels. The city depends on five main reservoirs: one has already gone dry and another is below 8% capacity. Officials have warned that the Karaj Dam holds only about two weeks of drinking water if conditions do not improve. Outside the capital, Mashhad’s reserves are reported below 3%, placing around 4 million residents at immediate risk.

What officials are saying

In October, President Masoud Pezeshkian warned that the water emergency was so severe Tehran might no longer be fit to serve as the national capital. He said, "If it doesn’t rain in Tehran by late November, we’ll have to [formally] ration water. And if it still doesn’t rain, we’ll have to evacuate Tehran." That prospect has provoked strong pushback: former Tehran mayor Gholamhossein Karbaschi called evacuation "a joke," and experts note relocation would be logistically enormous and would not solve underlying water shortages.

Causes: climate, policy and infrastructure

The crisis reflects a convergence of factors:

• Severe drought and climate change: Iran recorded its driest and hottest autumn in nearly six decades, and forecasts showed little rain in the near term.
• Longstanding water-management choices: Analysts point to decades of large-scale dams, deep wells and inter-basin transfer projects that often ignored local hydrology and ecological limits. Commentators such as Nik Kowsar have criticized powerful interests for promoting megaprojects that benefit connected actors.
• Agricultural demand: Agriculture accounts for as much as 90% of national water withdrawals, driven in part by policies favoring food self-sufficiency and water-intensive crops.
• Sanctions and geopolitics: International isolation limits access to certain advanced technologies and complicates cooperation with regional desalination leaders, while large-scale desalination also carries environmental and cost concerns.

Social and political consequences

The crisis is deepening inequality. Wealthier households can afford bottled water or private tankers; poorer families depend on charity or face life-threatening shortages. Water transfers between regions have fueled resentment and accusations that certain ethnic or regional communities are being shortchanged to supply others. Yale historian Arash Azizi warns of significant psychological and social consequences if the crisis persists.

"Actually cutting off the supply to households or to individual neighborhoods de facto reduces their consumption," said David Michel, senior fellow for water security at the Center for Strategic and International Studies. "But the underlying demand is still there."

Short-term responses and their limits

Authorities are trucking water into the city and imposing rationing measures, including nightly pressure cuts. Those stopgap measures reduce immediate suffering but do not address the structural gap between supply and demand or the financial shortfalls many municipal utilities face. Experts warn that without reforms, temporary measures only postpone larger failures.

Possible policy directions

Experts recommend a mix of measures to stabilize supply and reduce demand sustainably:

• Financial and pricing reforms: Improved utility financing and targeted volumetric tariffs (charging by volume) can help recover operating costs, incentivize conservation and protect basic access for low-income households.
• Demand management: Urban water efficiency, reduced leaks, modern irrigation, and incentives to grow less water-intensive crops would lower withdrawals from stressed sources.
• Supply investments and governance: Investments in treated wastewater reuse, small-scale local supply projects, transparent governance and anti-corruption measures are needed instead of politically driven megaprojects.
• Regional and international cooperation: Where feasible, technical cooperation and neutral channels to obtain sustainable technologies could help — though geopolitical constraints complicate this path.

Global lesson

Tehran joins other cities that have approached a so-called "Day Zero" — Cape Town and São Paulo experienced near-miss events that were averted by timely rainfall. Tehran’s forecasts are less promising, making it a stark warning for other arid metropolises, including parts of California and the U.S. Southwest. The situation underlines that climate impacts, poor planning and inequitable systems can combine to produce humanitarian risk in major cities.

Conclusion: Immediate relief efforts are necessary to protect vulnerable residents, but lasting resilience will require financial reform, better demand management, governance changes and targeted investments in sustainable supply. Without those, Tehran’s emergency could presage similar crises in other water-stressed cities worldwide.