Coming crackdown on data center noise likely won't bring relief to a community most affected

Nearly three years ago, residents of the Great Oak community began sounding the alarm about excessive noise emanating from a new Amazon data center next to their neighborhood south of Manassas. 

Now, at the urging of those residents, the Prince William Board of County Supervisors is poised to consider a strict new noise ordinance, one of a just a few in the nation designed to deal with the unique characteristics of data center noise. 

“The process has been slow but it’s starting to produce results,” said Dale Browne, president of the Great Oak Homeowners Association and a member of the county’s “data center ordinance advisory group,” which spearheaded the effort. He expects the proposed ordinance could be up for a vote in late June.

These Amazon data centers, behind the Great Oak subdivision outside Manassas, emit a constant, low-pitch roar that’s been the source of resident complaints for two years. Photo by Doug Stroud.

Still, the strict new ordinance won’t immediately solve Great Oak’s noise problem. First, though Amazon has cut the noise coming from its four data centers next door, measurements taken by a consultant indicate the noise from the complex will not comply with the new ordinance. If approved, the new rule would limit continuous noise in residential areas, even those next to data centers, to that of moderate rainfall.

Second, the community remains plagued by a low-frequency roar coming from the data centers, a type of house-penetrating sound that is not regulated by the current ordinance and will fail the new ordinance.

“My 7-year-old wakes up and says he thinks there is a spaceship outside our house,” said Carlos Yanes, whose home on Winged Elm Circle seems especially vulnerable to the noisy data centers. “It’s beyond frustrating that I can’t protect my children.”

Third, on the morning of Feb. 17, Great Oak residents awoke to dozens of Amazon emergency diesel generators blaring a new noise they had not heard before. The generators sounded like a “a hair dryer right on your ear,” said Yanes.

The generators, which apparently switched on because of a half-hour power outage, are not regulated by either the current or the proposed ordinance. Browne called the noise “the worst it has ever been.”

For its part, Amazon says it has done all it can and meets the county’s current noise limits. But it has indicated it does not intend to do more to comply with a new noise ordinance that does not yet exist.

“The data in our recently completed sound study demonstrates that (Amazon Web Services’) efforts have significantly reduced sound, and that AWS is in compliance with applicable law,” wrote Sarah Georgiades, Amazon’s head of community engagement, in an email to Browne.  

“I commend them for what they’ve done so far,” Browne said, ticking off Amazon’s quieting of noise from rooftop fans and wall vents. But he added, “They've got a chance to use the time between now and June to make some more progress and get ready for an ordinance that's going to have them in constant violation. And they're doing nothing.” 

“Waiting to finally do something once the noise ordinance changes because you will be forced to, is not being neighborly at all,” Yanes told Amazon in an email.   

New ordinance a 2-year effort

Only a handful of jurisdictions in the U.S. have written ordinances to deal with data center noise, and doing so in Prince William County was not easy.

The work began in the spring of 2022 as Great Oak residents tried to get Amazon to quiet its data centers. That turned into a broader effort, supported by county supervisors, to update the noise ordinance to deal with data center noise — its continuous nature and its vibrations at multiple frequencies.

In July 2023, the data center advisory group, consisting of county staff, residents and industry officials, was assembled to address noise and data center zoning issues. When the resident members complained in November 2024 that the industry representatives were impeding progress, they were removed.  

That helped move things along, Browne said, as the meetings were “less contentious.” With two consultants on board, the group reviewed the entire county noise code. They decided to keep existing prohibitions against such things as loud mufflers, party noise and loudspeakers — what is known as “impulse noise.” They also added restrictions on continuous noise — that is, noise that lasts for 10 minutes or longer. Those limits are especially low in neighborhoods — 52 decibels in the daytime, 47 decibels at night — where residents often complain about data centers’ never-ending drone.

Nelson Acoustics, a consultant to the ordinance-writing group, tested the new limits in several Prince William subdivisions. Measurements taken in early morning at four Great Oak locations found sound levels violated the proposed limits in more than half the places and frequencies tested. Two other locations tested off Wellington Road and Hornbaker Road, near data center clusters, also failed the new noise limits. Seven other Prince William subdivisions, three schools and four parks, none of which have data centers nearby, passed the noise tests.  

The consultants recommended that police and perhaps a specially trained public works unit enforce the new noise ordinance. Violations could be civil or criminal and subject to fines of up to $500, according to county documents. 

How the new regulations will affect Great Oak is unclear. Noise is additive, and the community of 291 homes will eventually be surrounded by up to 12 data center campuses with between one and four buildings each, if all planned projects go through. Nine are less than half a mile from the community. 

“The additive noise is a huge issue for me,” said Browne, but solutions for dealing with that have yet to be worked out.