By Chris Hancock 

Data centers house the hardware, such as servers and networking equipment, that underpin the digital services that most people use every day. Watching videos, storing files in the cloud, searching the internet, making video calls, using an AI chatbot, and processing credit card payments all depend on the continuous operation of data centers. 

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. 

Here are five important considerations about data center water use. 

1. A small share of national water use can still have a big local impact. 

While data centers represent a small share of global and national water use, their impacts are experienced locally. A single facility can withdraw an average of 270 gallons to 3.9 million gallons per day. While a facility at the low end of this range would have minimal impact, those at the high end could have a significant impact.   

Furthermore, data centers are typically clustered and are rapidly expanding into new areas, including water-scarce and rural parts of the United States. This expansion can strain local infrastructure and create challenges for water managers and operators. 

2. The timing of water use matters. 

A data center’s water use fluctuates throughout the year but typically peaks during hot and dry periods, when cooling needs are greatest. This is the same time that 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 force utilities to build, maintain, and finance new water infrastructure to serve these demands. 

Much of the current data center expansion is based on forecasts of future demand. If some proposed facilities are never built or existing facilities are later abandoned, utilities could be left operating and maintaining water systems that are larger than needed. 

3. Water withdrawn isn’t necessarily water returned. 

Data centers use water directly onsite for cooling, humidification, construction, and domestic uses. Most data centers are supplied by municipal drinking water systems, meaning they often use high-quality drinking water for cooling purposes that do not necessarily require it. 

Furthermore, much of the water withdrawn is consumed through evaporation and is not returned to the original water source. 

For a typical facility, 74% of the water withdrawn is consumed and unavailable for other uses within the water basin. By comparison, an average of about 12% is consumed from all public water supplies across the contiguous US. 

4. A data center’s water footprint extends far beyond the facility. 

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. 

Available studies suggest that indirect water consumption of a data center is 2.4 to 12 times greater than direct consumption. Water requirements for electricity generation depend on the energy sources supplying the grid, with renewables like wind and solar requiring far less water than nuclear or fossil-fuel power plants. 

5. We still don’t have the information needed to understand the full picture. 

Despite growing concerns, basic information about data centers is limited. 

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. 

These data can help analysts evaluate emerging trends and help communities anticipate and mitigate local and regional impacts. More broadly, greater data availability enhances transparency and ultimately trust. 

Learn more in the full issue brief, How Much Water Do Data Centers Use? And Why Does It Matter?.