Aurora council adopts new data‑center rules after weeks of resident complaints; lowers proposed noise limits

Aurora’s City Council voted March 24 to adopt new local rules that set separation, noise, testing and reporting requirements for data‑center facilities after weeks of public pressure from nearby residents, staff presentations and council debate. The council amended staff’s earlier proposal and approved a property‑line noise standard of 56 A‑weighted decibels during daytime hours (7 a.m.–7 p.m.) and 46 dB overnight (7 p.m.–7 a.m.).

The measures—packaged in two ordinances the council adopted that evening—create a local permitting path, require pre‑ and post‑construction sound and vibration testing by a city‑approved consultant, add operational reporting requirements and clarify enforcement mechanisms. Council members and staff said the package is intended to protect residents’ health and quality of life while providing a clear, enforceable regulatory framework for future facilities.

The issue dominated public comment. Dozens of residents described continuous low‑frequency noise they attribute to a nearby CyrusOne campus and asked the council to ban or strictly limit new data‑center development. “It never goes away,” Laura Evans told the council, describing constant chiller noise in her yard and urging stronger setbacks and enforcement. Several speakers also raised groundwater and air‑quality concerns; Ashley Statt, an environmental‑policy practitioner, urged higher on‑site energy and water‑efficiency standards and asked whether 25 percent on‑site renewable or storage was adequate.

Representatives of existing local facilities urged a balanced approach. Kevin Lennon of CME Group said CME has operated a data center at 2905 Deal Road for 16 years, described steps taken to reduce noise and emissions and asked flexibility for operational testing; he said his company was willing to reduce generator tests to quarterly. Council members and staff said some operational exceptions could be negotiated on a site‑by‑site basis, but that the new rules establish a consistent baseline.

Staff presentations showed the practical effects of different separation distances and property‑line decibel limits. City sustainability staff reported that the data centers in and around Aurora generated about $400,000 in property‑tax revenue for the city in tax year 2024 and that some facilities are not yet operating at full megawatt capacity. Planners used a combination of 1,000‑foot and 1,500‑foot buffer scenarios and a half‑mile (2,640‑foot) buffer to illustrate how many industrial parcels would remain available for development under each approach.

Council deliberations focused mainly on two tradeoffs: distance versus achievable noise reductions. Alderman Bade proposed a half‑mile buffer that staff and the city’s legal advisers warned could amount to exclusionary zoning; that amendment failed on a 5–7 roll call. Separately, Alderman Bogg moved to lower the property‑line noise target to 56/46 dB (day/night). That amendment passed unanimously and was incorporated into the ordinances the council later adopted.

Several other amendments were discussed but did not pass. Proposals for mandatory long‑term human health impact studies and for continuous, around‑the‑clock air monitoring at facility property lines were moved and debated but failed in roll‑call votes. Council members who opposed those amendments said the state Illinois Pollution Control Board and IEPA have primary regulatory authority over certain emissions and that some health studies can be long and costly; supporters argued local monitoring and health assessments would strengthen enforcement and resident protections.

What the council adopted

- Ordinance 260112: Zoning code amendments to define data‑center facilities, set conditional‑use rules and require development agreements as needed; adopted by roll call (11–1). Council amended relevant decibel numbers earlier in the process. - Ordinance 260092: New chapters creating an Aurora responsible data‑center ordinance and a data‑center privacy protection chapter (performance standards, operational reporting and enforcement); adopted by roll call (12–0).

Votes at a glance: key outcomes

- Approved: amendment lowering proposed property‑line limits to 56 dB (day) / 46 dB (night) (vote recorded 12–0 when amendment was adopted). - Failed: half‑mile (2,640‑foot) universal separation distance (vote 5–7). - Failed: motions requiring mandatory long‑term human‑health impact assessments and continuous property‑line air monitoring as part of the zoning ordinance.

What happens next

The new rules include preconstruction modeling and city‑supervised testing before final occupancy, plus the ability to require additional tests whenever new noise‑ or vibration‑producing equipment is added. Council and staff said the city will recruit independent testing consultants, with the developer reimbursing testing costs. Staff also noted an existing moratorium extension remains in effect for 30 days to allow rules and procedures to be finalized.

Mayor John Lash and planning staff said they will continue discussions with existing operators that predate the new ordinances to work out site‑specific remedies. City staff also told council members they would assemble enforcement procedures, identify certified testing vendors and publish guidance for applicants and neighbors about complaint processes and timelines.

Reporting and transparency

Council directed staff to publish compliance requirements and to require annual operational reporting from permitted facilities (energy use, on‑site generation or storage and test reports). Where evidence of noncompliance is found, the ordinance makes legal remedies and cost recovery available to the city, including administrative penalties and the ability to recoup enforcement costs.

Why it matters

Aurora faces a balance that other communities across the region also confront: the economic and tax benefits offered by large digital‑infrastructure projects versus documented resident complaints about noise, vibration, water use and localized air emissions. Council members framed the ordinances as a local attempt to set strong, enforceable standards while preserving legal and planning flexibility for site‑specific agreements.

Representative quotes

• Anonymous Aurora resident (public comment): “I implore you to do so, so that we do not have to fall back on another extension on that moratorium.”

• Ashley Statt (resident, environmental policy): “The proposed 25% peak load...seems like a low bar considering the potential impacts to our electrical grid and energy pricing.”

• John Curley (city staff): “The decibel scale is not a linear scale…so a few decibels can represent large changes in perceived loudness.”

• Laura Evans (resident): “It never goes away.”

For readers

Council packets, the adopted ordinances and staff exhibits include maps showing affected industrial parcels, the text of the new chapters (50 and 51), and the technical tables staff used to model decibel levels and distance attenuation. Staff said those documents will be posted to the city website. The city also said it will publish the names of approved testing consultants and instructions for how neighbors can file verified complaints.

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