Musk wants a self-growing Moon city in 10 years. Here’s when the water runs out

A study in Frontiers in Space Technologies estimated lunar water ice reserves at 600 million tons. A city of 1 million people would exhaust them in just over two years, or a century with 98% water recycling like on the ISS. A small settlement of 1,000–10,000 people would last several centuries.

• Estimated water ice in shadowed craters: about 600 million tons
• City of 1 million without recycling would exhaust water in just over 2 years
• With 98% recycling like ISS, supply would last a century
• Settlement of 1,000–10,000 people would last several centuries