I read every noise rule in Virginia that could reach a data center. There are 73 of them across 43 jurisdictions, and the one that stopped me was not a decibel limit. It was a budget line.

It is in a Loudoun County staff report from September 2016. The county was rewriting its noise standards and someone had asked what it would cost to regulate tonal noise, meaning the narrow-band hum that people describe when they complain about a data center, as opposed to overall loudness. Staff answered in the fiscal note. A thousand dollars, for software and training.

The county passed on it.

One technical thing explains why that matters. Virginia measures noise in A-weighted decibels, a scale built around how the ear responds to quiet sound. Human hearing is poor at low frequencies, so the scale discounts them — about 39 decibels at 31.5 hertz. 

The hum is down there. A meter set to dBA is, by design, subtracting most of the thing people are calling about.

Loudoun’s staff report explains the decision. Regulating tonal noise, it says, “may place the County at a competitive disadvantage with other regional jurisdictions when competing for businesses such as data centers.”

Loudoun has never issued a noise violation against the Vantage campus in Sterling.

Prince William tried harder, and its story is worse.

The county convened residents into a Data Center Ordinance Advisory Group and set them to work with professional acousticians. Donna Gallant represented Amberleigh Station. What they produced measured sound in nine octave bands down to 31.5 hertz, catching the low end dBA throws away.

The county raised every one of their 18 values by 6 decibels.

I want to be careful here, because this is the kind of claim that sounds like an accusation. It is not an inference. The staff report for the October adoption says it plainly: the levels “would be raised by 6 decibels over the levels recommended by the Noise Consultants.”

On Sept. 17 a deputy county executive wrote to one of the group’s own members that data center representatives “understand the ordinance won’t impact their business, but they are concerned with the larger message this sends about the county’s business atmosphere.” 

Nobody argued the standard would cost them anything. The objection was to how it would look.

The next day Gallant told InsideNoVa that the official “has gone rogue and done his own thing and gave us the straight middle finger.”

Three weeks later the board dissolved her committee, as an item added to the agenda that had not been published on it. Twenty-one days after that it adopted a different measurement approach entirely. The residents’ table is still in the county code, under a line explaining that its values “are advisory and do not constitute the legal compliance test.”

I looked for a jurisdiction that had done better. Of those 73 rules, 40 set no number at all. Most turn on whether sound is “plainly audible” inside a neighbor’s house, which is enforceable against a car stereo and useless against a hum. Eight say anything about tonal sound. 

Rockingham County has no noise ordinance. Prince George County caps a battery storage installation at 20 decibels next to a home and caps a data center at nothing.

So Prince William’s weakened standard is the strictest thing Virginia has.

In Chesapeake, 200 miles away, residents asked the planning staff this summer for stricter limits and were refused. Staff wrote that its recommendation already “reflects the most stringent adopted noise standards we identified in Virginia, specifically the standards established by Prince William County.”

On Aug. 18 the council adopted a data center ordinance with no noise limit in it. A substitute offered from the dais stripped the numbers out and left them to be written during the eight-month moratorium the city adopted in July. Virginia Beach paused its own the same evening, for twelve months.

So the number is still open, and the staff position going into it is that a standard Prince William raised by 6 decibels is as strict as Virginia gets.

Asked on Aug. 11 why she would not order a statewide pause, a spokesperson for Gov. Abigail Spanberger said Virginia “is showing what it looks like to be a national leader on making sure data centers pay their fair share for the energy they use, listen to the needs of local communities, and adhere to stricter environmental, water, and noise pollution standards.” 

Two days later, in Alexandria, the governor said it herself, and added that whether a community hosts data centers “is a local choice.”

I have read what the localities did with that choice. I would not describe it that way.

There is one fix I would ask any of them for, and it isn’t a decibel limit. No Virginia locality requires an applicant to measure ambient sound at a site before anything is built. Without that, a resident says it got louder, the county says the reading is under the limit, and both of them are telling the truth with nothing on file that could settle it.

A baseline costs a few thousand dollars on a project spending hundreds of millions. Prince William already had residents willing to do the work.

Loudoun votes Sept. 15 on whether to pause new applications while it finishes writing stricter noise standards. Chesapeake has eight months. Virginia Beach has 12. Three jurisdictions are about to set the numbers. Loudoun priced the fix at $1,000 a decade ago.