Data centers may have a big geographical footprint, but they don't necessarily use a lot of water compared to other industrial operations or other facilities that are water intensive.
Take for example the nearly 800-acre data center recently approved by the city of Joliet. According to other media accounts, the 1.8-gigawatt Joliet Technology Center will be about the size of New York City's Central Park.
Joliet Public Utilities director Alison Swisher said the amount of water use the company gave for that complex of buildings is an average of 120,000 gallons per day, or 3.6 million per month. Data centers are increasingly moving to closed-loop cooling systems, which cost less than using a constant stream of water.
"And a lot of that water wasn't even for the closed loop. The closed loop — you fill it, and then the water stays in there, and it minimally needs recharging. Every 10-15 years, they drain it and refill it," said Swisher.
McLean County doesn't yet have a hyperscale data center like the one slated for Joliet. But the prospect of new data centers locally has stirred concerns about potential impacts on water supplies. WGLT gathered some data to help put data center water use in context.
In Joliet, Swisher said the city's agreement with their data center company has very specific caps on the amount of water it can use on an average basis per day.
"A lot of the water that they were asking us for was actually for irrigation purposes, because they wanted the campus to have a lot of landscaping, and look nice," said Swisher.
In addition to average amounts, the pact also sets a maximum per-day limit.
"That was something that was very important to our council, to make sure that we wouldn't be using water that's a very precious resource to us," said Swisher.
Golf courses
You know what also has a lot of landscaping and looks nice? Golf courses.
Water use varies significantly depending on the climate. Courses in arid areas use lots more. The U.S. Golf Association said the typical U.S. golf course uses 9.4 million gallons of water per month. Put another way, the Joliet data center uses less than 40% of the water used by the typical golf course in the nation, calculated on a 30-day month for the data center.
Some golf courses use gray water, repurposed sewage effluent after treatment. Right now, Bloomington-Normal sends that downstream to the Gulf of Mexico. A bill signed into law last August would allow the Decatur Sanitary District and the Bloomington-Normal Water Reclamation District to sell its treated gray water to other entities, such as golf course operators or data centers.
The specialty legislation for Decatur and Bloomington-Normal could be a test case because the data center debate has raised the profile of water scarcity in Illinois.
"The WateReuse Association just started an Illinois chapter," said Swisher. "That group is working with the state to find ways to streamline the permitting process and help encourage that ability to use the gray water for industrial purposes."
The state plumbing code and Illinois Environmental Protection Agency rules remain barriers to any widespread industrial use of gray water.
As an aside, some water-scarce communities actually try to close the loop between effluent and drinking water. San Diego sends its treated gray water back into the drinking water treatment process.
"We know as technical professionals that any water can be treated to drinking water standards," said Swisher.
There are two considerations on that issue. One is public perception. No one really wants to think about drinking water that came out of a sewage treatment process. That is even though everyone that uses water from the Illinois River downstream of the Des Plaines River and the City of Chicago essentially does that already, however diluted it might be.
The other challenge is cost. Higher level treatment would be needed to make gray water into drinking water. Just one example is the EPA standard for phosphorous. Right now, sanitation districts can release water that has 0.5 parts per mission [ppm] of phosphorous. The EPA standard for drinking water permits is 0.05 ppm of phosphorus. It would be expensive to meet that standard, and Illinois still mostly has adequate surface water and aquifer options, for now.
Car washes
Other things people want to look nice are their automobiles. Car washes use a lot of water too.
Town of Normal Water Director John Burkhart said car washes use 350,000 to 800,000 gallons per month. The low months are not in the winter. Burkhart said some of the heaviest daily car wash use comes following big snow or other messy weather when people want to get the road salt and other muck off their vehicles.
According to Town of Normal records, one popular car wash used 8.1 million gallons in the last billing year, for an average of 677,041 gallons per month. In other words, it would take about five of those car washes to equal the planned water use at Joliet's data center. A very unscientific car-washes-near-me search showed at least 21 car washes in Bloomington-Normal. So, a fair amount of water goes to that particular use.
Other industrial water consumption
Alison Swisher from Joliet said water use by the hyperscale data center there will not be out of scale compared to other industrial uses in the area.
How about Bloomington-Normal industries? The Bridgestone plant in Normal has made large tires for mining and other really big vehicles for decades. Municipal records showed two main water accounts at Bridgestone. Taken together they averaged 2.7 million gallons per month in the last billing year. Or, Bridgestone represents about three quarters of a data center like Joliet's.
Auto plants use a lot of water, mainly in the paint shop. Municipal records show Rivian used 71.3 million gallons in 11 of the last 12 months. (WGLT excluded one month because of an anomalous amount, possibly due to a change in metering.) The 11-month monthly average is 6.5 million gallons — meaning, Joliet's data center would use about 60% of what Rivian does.
Young people
You know what else consumes a lot of water? College students.
Seven of the top 10 users in the Town of Normal are ISU accounts, including residence halls. Precise numbers for those billing accounts were not immediately available. But taken together, they generously exceed Rivian’s water use.
Now, Rivian has spent billions of dollars putting up the original addition to the plant and the new R2 facility. It does employ thousands of workers. Data centers employ far fewer. If you consider property tax dollars, however, public accounts suggest the Joliet data center stacks up well with Rivian’s investment. The Joliet Technology Center will cost $20 billion to put up.
