Why meeting a noise limit may not be enough when a data centre hums day and night.
Imagine a neighbor hosting a loud party. The music starts in the evening, someone complains, and by midnight it is over. Now imagine a mechanical hum from industrial cooling fans, transformers and generators that is present when you wake up, when you work, when you try to sit outside and when you go to sleep. That sound can continue through the night and return the next morning, with no clear end. A single decibel limit may not capture the difference between a temporary disturbance and a continuous mechanical drone.
Most of us encounter noise rules through familiar neighborhood disputes: parties, leaf blowers, construction work or loud music. Yet local laws vary widely. Some already regulate continuous industrial noise and some do not adequately distinguish it from short events. We should not claim that every ordinance was written only for parties. A time-of-day decibel ceiling can miss the cumulative effect of a sound that never stops.
What sound-limit compliance does and does not measure
A data centre can meet an A-weighted decibel limit and still generate a persistent low-frequency sound that neighbors find intrusive. A-weighted decibels, often shown as dBA, are useful but do not fully characterize tonal or low-frequency hum. To assess a facility properly, regulators also need sound-frequency data, the difference between the noise and the normal background sound, and measurements at homes during real operating conditions, including at night.
Virginia's Joint Legislative Audit and Review Commission documented resident complaints involving constant data centre sound. Its study found that, in a few cases, noise from data centres has negatively affected nearby residents and that such impacts can be difficult to resolve. The Commission recommended tools for better preconstruction modeling and local enforcement, including low-frequency sound metrics. Read Virginia's data centre report.
What the law says, and what the law ought to protect
Meeting an applicable ordinance is not, by itself, a legal violation. It would be inaccurate to declare a facility legally noncompliant solely because its noise is continuous. An additional question for policymakers is whether the standard adequately accounts for sustained or tonal sound at nearby homes. Where measurements identify impacts that a current standard does not address, regulators can assess whether updated methods or permit conditions are warranted.
That change is already happening. Prince William County, Virginia, introduced specific enforcement provisions for steady tonal noise effective May 1, 2026. Its county guidance explicitly identifies the kinds of whines, hums, rumbles and buzzes associated with commercial mechanical equipment and data centres. This is a concrete acknowledgment that conventional noise measurement alone may not be sufficient. Read the county's noise enforcement guidance.
Distance matters, but distance alone is not a noise measurement
We should record how far a data centre is from the nearest residence, measured to the receiving residential property boundary where possible. A facility 300 metres from homes is a different planning question from one several kilometres away, but distance alone does not predict how loud it will sound. Topography, cooling equipment, background sound, wind and the design of sound barriers all matter. Measuring the actual sound at the affected property is essential.
That is why our Observatory tracks both proximity and sound. Where the evidence exists, a project profile should show the local day and night limits, actual measured sound in dBA, available low-frequency readings in dBC, whether the facility is currently operating, how sound was measured and whether it exceeds the applicable legal standard. No data means not rated, rather than an assumption of compliance or a fabricated distance.
What governments should require
Before allowing large data centres close to existing neighborhoods, local governments should require independent sound modeling under representative peak cooling and nighttime conditions, and publish the results. After a facility opens, require independent monitoring at the nearest homes, with accessible complaint procedures and published follow-up results. Measurements should address sustained tones and low-frequency sound, not merely the loudest brief moment. Conditions on operating permits should specify corrective action where applicable limits are breached.
Virginia's county and state-level work shows that this is an actionable policy choice. The objective is not to prohibit digital infrastructure. It is to ensure that the people living alongside it have rights backed by measurements, evidence and enforceable standards.
Our research question for every project: What noise will nearby residents hear at 2 a.m., how often will they hear it, how is it measured, and who has the authority to fix the problem?Send the evidence
Have a noise study, permit, independently measured reading or documented complaint related to one of the projects in our tracker? Open that project in the 8ALTA AI Infrastructure Observatory and select Submit evidence or dispute this record. Please provide the original source, measurement date, distance to the receiving property and the applicable ordinance.
Primary sources: Prince William County noise ordinance guidance; county steady tonal noise enforcement; Virginia JLARC Data Centers in Virginia, Chapter 6; Fairfax County Data Centers Report and Recommendations (January 9, 2024).