Why do data centres consume so much water?

Why do data centres consume so much water? To a casual observer, it might seem counterintuitive that data centres require water at all.

I mean, our home air-conditioning systems are simply plugged into electrical sockets and turned on, so why do data centres need water?

Show me the water

There are two main reasons why data centres need a massive amount of water, especially in the hot tropics that make up most of Southeast Asia.

• Evaporative cooling

Most water consumed by data centres is through cooling towers, where water evaporates as the primary mechanism to remove heat.

Sure, operators can use air-cooled chillers. However, these are less efficient, especially in hot climates. Expect to use significantly more energy.

Real-world deployments are, of course, a lot more complex and nuanced. In general, it boils down to a decision between using more electricity or more water.

• Blowdown and refill

Data centres also rely heavily on water for transferring heat from hot data halls to cooling systems. As this happens within a "closed" loop, water doesn't evaporate.

However, water channelled continuously through pipes does accumulate minerals and other contaminants over time. Organic matter such as algae can grow, too.

The result? Scaling, corrosion, and biofouling.

Chemical additives and water treatment can extend its usable lifespan. But ultimately, the water must be discarded ("blowdown") and topped up with fresh treated water.

Massive scale

Now consider this: Data centres built today are far larger than the ones commissioned just a few years ago. Indeed, some of the current data centres pack up to 10 times the capacity in megawatts.

As a result, the water consumption of data centres has increased by a similar factor, raising concerns about sustainability and water shortages.

On that front, Malaysia has just announced that it will spend over RM5 billion to develop 3 reservoirs and 3 water treatment plants in Johor within 5 years.

How much water again?

How much water does a typical data centre consume? This is where things get... interesting, as I'm not aware of any industry-wide studies that track water use across data centres.

We can't estimate reliably, as:

• Workloads differ across data centres.
• Differences in cooling systems, configurations.
• Local climates massively impact cooling efficiency.

So we don't know exactly how much water data centers need. And data centre operators tend to keep mum on operational details.

But maybe the time has come for the industry to rally and work together to hopefully reduce water use. What do you think?