Cheyenne Mayor: Data center water use is far below city supply

CHEYENNE — Amid mounting concerns over how expanding data center development could strain Wyoming’s limited water supply, Cheyenne Mayor Patrick Collins told state lawmakers Thursday that the city’s existing data centers consume only a fraction of the water used by other local industries and residential lawn irrigation.

At a meeting of the Wyoming Legislature’s Select Water Committee, Collins discussed consumptive use of water by data centers in Cheyenne.

He began by saying although discussions regarding data centers in the city have ramped up recently, data center development has been going on for almost 20 years.

“Greenhouse Data — today, it’s called Lunavi — opened their first data center (in Cheyenne) in 2009,” Collins said. “NCAR and Microsoft followed in 2012, and we’ve had constant or continuous data center construction ever since.”

Collins said Cheyenne currently has “a number” of small data centers, as well as three data center campuses with 13 operating data center buildings.

Three more data center campuses and seven data center halls are under construction.

While there are many concerns associated with data center construction and operation, Collins said he understands water is among the top due to water supply shortages across Wyoming.

He stated that data centers use approximately 200 acre feet of water per year, which is equivalent to 1.48% of all the water used in Cheyenne in a day, and less than 1% of all the water that Cheyenne has available to use annually.

“To put that in context, a pivot … irrigating alfalfa in this part of Wyoming uses about 3.3 acre feet of water per acre,” Collins said. “If a quarter-section irrigates 125 acres, it would result in about 412 acre feet of water being used annually. All of our data centers today use less than half that amount.”

For further comparison, he presented the annual amount of water used by other local entities.

He said a single-family home in Cheyenne uses around a quarter of an acre foot of water annually; a single coffee shop uses two acre feet, and Collins noted there are 30 coffee shops in Cheyenne; a fast-food restaurant uses two acre feet per year; grocery stores use around five acre feet; an automatic car wash uses 18 acre feet per year, and Collins noted Cheyenne has 14; the Walmart Distribution Center uses 25 acre feet; Laramie County School District 1 uses 264 acre feet, and 204 of that is used solely to irrigate the lawns around schools; and the city of Cheyenne uses 2,629 acre feet to water lawns.

Collins also referenced data centers’ more modern use of closed-loop water systems to cool their computers, which is a recirculating network that uses the same water continuously for heating or cooling, minimizing water loss and contamination.

He said he spoke to two local developers who have centers currently under construction in Cheyenne about their closed-loop systems, and both said their system uses around two acre feet of water, which is equivalent to the amount of water eight single- family Cheyenne homes use in one year.

Collins said one other big advantage of developing in Cheyenne is that the city’s cool weather limits the need to use the installed cooling systems. He said a developer told him that about 80% of the time, the outside air will cool the system, and therefore operators do not have to use their technology.

“After that, the data center only uses water for domestic uses like bathrooms and coffee makers, landscape irrigation, etc.,” Collins said. “I like to compare data centers with an office building with the same number of employees once they’re operational.”

Some residents and state leaders have speculated recently that Cheyenne will eventually house more than 70 data centers. But Collins said Cheyenne’s Board of Public Utilities ran the numbers and found that even if this were to happen, officials estimate that all the data centers combined would use about 400 acre feet of water per year — around 3% of the city’s current water usage, and around 1.8% of the 22,000 acre feet the city has available annually.

Although the committee meeting was mostly in regard to water usage, Collins mentioned other rules and regulations data center developers must conform to when looking to build in Cheyenne.

“In my position as mayor, I meet with data center companies regularly as they’re looking at Cheyenne, learning about the projects I find very interesting,” Collins said. “I take the time to share Cheyenne’s expectations during these conversations. I know today your focus is on water, but I want you to know that our expectations of the company will be to do no harm when they come into our community.”

To mitigate any harm, Collins said data center developers are required to use Black Hills Energy’s Large Power Contract Service Tariff, which requires large-scale users to pay 100% of the cost of getting power to the facility so there is no impact to homeowners and businesses.

Additionally, he said, developers are required to pay for every aspect of their electrical services, preventing a rise in utility costs from passing on to homeowners and small business owners.

Collins ended by saying while a few data center developers have requested he sign a nondisclosure agreement, he has refused, stating he does not think it’s appropriate to do so as an elected official.

“I think that Cheyenne and Wyoming are benefiting from data center development, looking at our communities at this time,” he said. “It’s allowed us to understand the benefits and the challenges communities have had with earlier data center development from the late 1990s and early 2000s.

“We now have a large power service contract. We understand water usage, and we now require technology,” Collins continued. “We have noise and light regulations. So I think we’ve learned a lot over these periods of time.”

This story was published on May 8, 2026.