Why Do Data Centers Need Fresh Water? 

We’ve all seen it – “A 100-word email written by AI uses the same amount of freshwater as a water bottle.”  

But why do data centers need fresh water? And how does it consume water? And why can’t the water be reused? These are a few of the questions we’ve seen, plus questions about why we can’t use fans, AC, or saltwater. So let’s figure it out.  

Why Do Data Centers Need Fresh Water?

AI data centers are warehouses full of computer servers running on electricity. This electrical energy produces heat. To prevent both the facility and the servers from overheating and breaking, they need consistent cooling.   

This is where water comes in. Many data centers use evaporative cooling to cool their facilities, a process in which hot air is cooled by cold water, forming steam. Fans then push this hot air out of the data center — around 80% of the water used evaporates during this process.

Beyond direct water use, AI data centers often rely on electricity generated by power plants that use steam and cold water to produce energy. We also can’t forget the water used in the manufacturing process for all of the servers, chips, and other materials used by data centers themselves. 

Why Can’t Data Centers Re-use Water?

Most of the water used is lost during cooling, but the remaining water is recycled a few times to help cool the servers. However, over time, this process leaves behind salt, bacteria, and mineral deposits as water evaporates. These can cause clogs in cooling systems and corrode equipment. To stop this, datacenter operators must continually add new freshwater to the system and discharge over-cycled water as wastewater.  

Why Can’t Data Centers Use Saltwater?

Saltwater would leave behind salt and other mineral deposits as it evaporates during cooling. Similarly to over-cycled freshwater, this can cause clogs and corrode equipment; thus, it is not a suitable substitute.  

Why Can’t Data Centers Use AC or Fans to Cool the Servers? 

Historically, data centers did rely on AC and fans to cool their facilities. But many data centers have switched to evaporative cooling because it’s more energy and cost-efficient and can handle higher temperatures. The trade-off? Higher freshwater consumption – all at the expense of people, communities, and our planet.  

What is Friends of the Earth Doing to Address This? 

We’re calling for a national moratorium on data center construction NOW to ensure we have clean air and water for our future generations.  The expansion of the AI industry is straining our limited water and energy resources, often in areas most impacted by extreme heat and weather events. Larger data centers can use up to 5 million gallons per day – enough for a town of up to 50,000 people. This directly threatens the survival of people living near data centers and our climate.