Growth in Artificial Intelligence (AI) and other cloud-based computing services is driving an unprecedented expansion of data centers across the globe. As data centers have become much larger and more concentrated, concerns about impacts on water and energy systems have intensified. This issue brief summarizes what we know about data center water use and addresses common misunderstandings. While data centers represent a relatively small proportion of global or national water use, data center water use can be locally significant, especially in water-scarce and rural areas. The lack of standardized reporting on the number, size, location, and water use of data centers makes it difficult for communities, water managers, and decision-makers to understand and adequately address potential impacts. 

1. While data centers represent a small share of global and national water use, their impacts are experienced locally. A single facility can withdraw from a daily average of 270 gallons to 3.9 million gallons. For a typical facility, 74% of the water withdrawn is consumed and unavailable for other uses within the water basin.  

2. Water use fluctuates throughout the year but peaks during hot and dry periods, when other demands are also high and supplies may be most constrained. Water utilities build their systems to reliably meet peak demands, so a highly variable customer can drive new infrastructure needs and costs.  

3. The water demands of large data centers differ sharply from most commercial buildings, and these differences may create unique challenges for municipal water systems serving them. They withdraw far more water than most commercial water users; concentrate their use during the hottest periods; and consume a much larger share of the water withdrawn.  

4. Data centers also use water indirectly — to generate electricity and manufacture equipment. These indirect uses of water are typically much larger than direct uses but are often ignored in water use reporting.  

5. More and better water and energy data are needed. The lack of standardized reporting on the number, size, location, and water use of data centers makes it difficult for communities, water managers, and decision-makers to understand and adequately address potential impacts.