CyrusOne Data Center Disputes: The Chandler Hum That Wrote the Nation's First Noise Ordinance, and the Illinois Fights Since

The Chandler story is the reason this site keeps telling people to document before they sue. Neighbors of the CyrusOne campus in Chandler, Arizona started complaining about a constant hum from cooling equipment in 2014. Nobody filed a lawsuit. The complaints accumulated, the city applied pressure, and mitigation followed in 2018.

Then Chandler did the thing that actually changed the industry. On December 5, 2022, the city unanimously passed the first data center noise ordinance in the nation, effective January 5, 2023. It requires pre construction community meetings, a paid noise liaison officer, a baseline acoustic study before operations begin, a standard that operations must not raise neighborhood sound above that baseline, five years of annual noise studies, and generator testing protocols. Chandler went on to reject a subsequent data center proposal in 2025. Our Arizona page covers the full sequence, and our noise limits guide reproduces what the ordinance actually requires.

Note what the Chandler ordinance does not do. It sets no fixed decibel number. It measures the facility against the neighborhood as it sounded before the facility existed, which is a harder standard for an operator to satisfy and a much easier one for a resident to prove. That design choice came out of a decade of complaints from people who could hear the difference and could not point to a number that captured it.

CyrusOne's Aurora, Illinois facility began operating in April 2025 and, per NPR Illinois reporting, residents complained about constant noise immediately. Aurora's mayor described the city's answer in procedural terms: the approach, both legally and legislatively, was to adopt noise limits at the property line.

The limits Aurora adopted are 56 decibels during the day and 46 decibels in the evening starting at 7 p.m., measured at property lines, and they apply to all ten of the city's data centers rather than to one company. Aurora initially tried to enforce sound using Illinois's nine octave band system and switched to straight decibel measurement after concluding the band approach was too complex to administer. The city's chief development services officer described the problem plainly: each of the nine bands carries its own permitted level, which produces variable decibel levels across all of them. Sound mitigation work at the site was expected to be complete by August 2026, with open questions about rooftop versus ground level chillers and about wind carrying sound to neighborhoods farther away.

Aurora's sequence is worth studying by anyone facing a facility already under construction. The city did not sue and did not need a class. It wrote a number, attached it to the property line, and applied it to every operator equally, which is both harder to challenge and easier to enforce than a facility specific condition. Our noise lawsuit guide covers what happens when a city will not do that and a private nuisance claim becomes the only route.

On April 7, 2026, the Sangamon County Board granted zoning for a CyrusOne campus in Talkington Township near Waverly, on roughly 280 acres of farmland in the 13000 block of Thayer Road. The vote was 17 to 10 with one abstention, and the county's adopted minutes record that "the resolution was adopted and the zoning was granted." The mechanism matters: this was a conditional permitted use inside the existing Agricultural district, not a rezoning and not a variance. The county's own staff report says the professional staff's opinion was that the proposed use "can be analogized to the operation of a large grain elevator and granting a conditional permitted use within the Agricultural zoning classification best protects the surrounding area which is agricultural." Our full report on the approval walks through the record. Per NPR Illinois, the project is reported at roughly $500 million, would draw about 600 megawatts at full operation, and would create roughly 500 construction jobs over several years and about 100 permanent positions. Capitol News Illinois separately reported the Sangamon County facility among Illinois data centers on track for state tax credits, and noted that CyrusOne's Aurora data center received state backing in 2024.

CyrusOne committed to funding electrical infrastructure upgrades and to using a closed loop cooling system to reduce water consumption, and said it planned to dredge Waverly Lake to extend its viability as a water source. County estimates put annual property tax revenue at roughly $6.5 million once operational, against $20,000 to $50,000 a year from the land as farmland today, with the county, the North Mac School District, and other local bodies sharing it.

The objections were the ones this site sees everywhere: diesel generator noise and emissions, strain on the electrical grid, and the risk of higher utility costs. One speaker asked the board to listen to the community and take more time for research. And opponents questioned the company's credibility by citing the noise complaints at its Aurora facility, which is the practical reason a company's record in one town is not a local matter. It becomes an exhibit in the next town's hearing.

CyrusOne, for its part, states publicly that it strives for a lasting positive impact in every community where it operates, that its presence brings direct investment, job creation, and infrastructure development, and that it collaborates with local, state, and national government officials to understand each community's unique needs. Nothing on this page is a finding that the company violated any law or ordinance.

Two American cities have now regulated data center sound because of complaints about CyrusOne campuses, and neither needed a lawsuit to do it. That is the fastest available path and it is worth trying first. Log the sound with dates, times, weather, and how it affects sleep. Take readings at your own property line. Find out whether your city or county has a numeric limit, an octave band table, or nothing at all, and file every complaint in writing so the record exists. Our guide to documenting data center harm is the checklist, and noise limits by jurisdiction shows what other places require, including Chandler's baseline standard.

If a CyrusOne project is proposed rather than built, the Sangamon County hearing is the model for what works: show up, put the company's record in other towns into the record in yours, and ask for conditions in writing before the vote rather than mitigation promises after it. Our guide to fighting a proposed data center covers the approval sequence, and zoning appeal deadlines by state covers the clocks that start the moment a decision is made. Illinois's data center litigation is on the tracker in Grayslake and Joliet.

If a facility is already operating and the noise has not stopped, a claim may exist. Our free case review connects you with an independent attorney in our network who handles data center cases in your state, at no cost and with no obligation.