Everyone Says Data Centers Use a Lot of Water. But What Does “A Lot” Actually Mean?

We warned about water stress in 2024. It has hit home. | AI generated.

"Data centers use millions of gallons of water every day."

You've probably heard that statement before.

Maybe you've even repeated it.

But let's stop for a second.

What is a lot of water?

A million gallons sounds enormous.

Three million gallons sounds even bigger.

But unless we have something to compare those numbers to, they're just numbers.

The Virginia Department of Environmental Quality (DEQ) recently released a report examining groundwater availability in eastern Virginia (available here: https://www.deq.virginia.gov/groundwater-report).

Instead, it left me with a lot more questions.

And I think those questions are more interesting than the headlines.

Before We Talk About Water Use...

Let's define a few things.

When someone says a facility "uses" water, what do they mean?

Did that water disappear forever?

Was it recycled?

Was it returned to a river?

Did it evaporate?

Those are very different things.

Engineers typically separate water into three categories.

Withdrawal is water taken from a source like a river or underground aquifer.

Consumption is the portion that doesn't immediately go back because it evaporates or becomes part of a process.

Discharge is water that's treated and returned to the environment.

Those three numbers can be dramatically different.

So before we compare industries, it's worth asking:

Which number are we talking about?

So...What Does a Million Gallons Look Like?

Let's make the numbers real.

An average family of four uses roughly 300 gallons of water each day.

That covers showers, laundry, dishes, toilets, cooking, drinking, and watering the yard.

At that rate...

One million gallons could supply about 3,300 homes for one day.

Three million gallons?

About 10,000 homes.

Now we're beginning to understand the scale.

But here's another question.

Is Three Million Gallons Unusual?

Not necessarily.

Large industries have used millions of gallons of water every day for decades.

According to DEQ's report, two paper mills accounted for roughly 43% of the reported groundwater withdrawals in the study area last year. That is nearly half of all the groundwater pumped from the aquifer in that region. Put simply, if ten buckets of water were taken from the ground, about four or five went to just those two facilities.

Think about that.

The groundwater challenges discussed in this report didn’t begin with data centers.

And before we all grab pitchforks and torches and go marching off to harass the nice folks at the West Point paper mill—let’s take a breath.

These issues didn’t appear overnight, and they certainly didn’t start with data centers. They’ve been around for a long time, shaped by a whole mix of industries and demands, not just one headline-grabbing newcomer.

What about other facilities?

Before deciding whether a million gallons is "a lot," let's put some numbers next to things we encounter every day:

The point isn't that one use is good or bad.

It's that context matters.

For example, my neighbors in Chesterfield County are upset about the Google data centers being built.

I understand why.

For years, people have watched the county approve more apartments, more townhomes, more subdivisions, more warehouses, and more commercial development. Roads feel busier. Schools feel fuller. Trees disappear. Infrastructure always seems to be trying to catch up.

Then data centers show up.

They are large, unfamiliar, and tied to headlines about enormous power and water demand. Of course people are going to ask whether Chesterfield is growing too fast and whether the county has fully considered the cumulative impact.

That is a fair question.

But it is also worth looking at the entire picture.

Thousands of new homes have been built or approved across Midlothian, Hull Street, and the county’s western growth corridors. Every new apartment, townhome, restaurant, school, warehouse, and subdivision adds water demand.

A single apartment building may add hundreds of residents. A large subdivision may add hundreds of homes. None of those projects creates the same reaction as a data center, but together they place steady pressure on the same roads, utilities, schools, and water systems.

So the question may not be whether data centers use a lot of water.

The better question is: What happens when you keep approving growth across every category and then add another large user to the system?

At some point, people are going to wonder whether the infrastructure was ready for any of it.

Here's Another Question...

In the DEQ report on groundwater in eastern Virginia, one term keeps coming up: aquifer.

What exactly is an aquifer?

Most people picture an underground lake.

That's not what it is.

An aquifer is more like a giant, water-filled sponge buried underground.

Water fills tiny spaces between sand and rock.

Wells pull water from those spaces.

The challenge isn't simply how much water is down there.

It's how quickly you can remove it without causing problems.

Think of it less like a retirement account that only gets depleted, and more like a bank account with both withdrawals and deposits.

Water is constantly being added back into the aquifer through natural recharge—rainfall soaking into the ground, water slowly seeping through soil and rock, and in some areas, leakage from rivers and streams. It’s a slow, steady process, not a sudden refill.

On top of that natural system, Virginia is also actively accelerating recharge through programs like SWIFT (Surface Water and Wastewater Infrastructure for Tomorrow), which treats wastewater to a very high standard and then injects it back into the aquifer to help restore groundwater levels.

So the real question is not just how much water is being withdrawn. It is whether withdrawals, along with natural and managed recharge, stay in balance over time. Groundwater is not a one-way drain. It works more like a system where inflows and outflows both matter.

What I Found Most Interesting

The DEQ report isn't really about data centers.

It's about capacity.

How much additional demand can eastern Virginia's groundwater support?

According to the report, not much.

That's true whether the next large water user is a paper mill, a manufacturing plant, or a data center.

Data centers have become the face of the conversation because Virginia is building more of them than anywhere else in the world.

But the report reminded me of something important.

The aquifer didn't become stressed overnight.

And one industry didn't create the problem by itself.

Maybe We're Asking the Wrong Question

Instead of asking:

"Do data centers use too much water?"

Maybe we should ask:

• Compared to what?
• Is that water withdrawn or consumed?
• Where does it come from?
• Can it be recycled?
• Is it drinking water, reclaimed water, surface water, or groundwater?
• How much can the local aquifer sustainably support?
• Would another cooling system change the answer?

Those questions are harder.

They're also much more useful.

Because numbers without context don't inform people.

They simply trigger emotions.

And if Virginia is going to make good decisions about its future, we'll need a lot more context and a lot fewer headlines.