Prince William County’s Board of Supervisors voted 5–2 on Oct. 28 to adopt a new noise ordinance aimed chiefly at low-frequency, continuous noise from data centers.

The newly adopted standards use a C-weighted sound metric for enforcement while retaining octave-band analysis as a technical advisory tool for staff and operators. The ordinance becomes effective six months after adoption to allow the county to hire and train enforcement staff and to give businesses notice.

The vote followed a lengthy public hearing that drew several hours of testimony from residents who said they suffer sleep disruption, vibration and other health effects they attribute to nearby data centers. Residents and community groups urged stricter limits, mandatory octave-band enforcement, and enforcement mechanisms that would identify the source of tonal noise. Industry representatives and local businesses urged caution, noting costs and technical challenges of retrofits and asking for phased or grandfathered treatment of existing facilities.

Deputy County Executive Wade Hu told the board the final ordinance was developed with acoustic consultants and county staff. The county will staff a new enforcement unit, purchase monitoring equipment and begin proactive ambient readings once the ordinance is in effect; staff estimated initial implementation costs and requested funding at the meeting. The board also directed staff to return with a report on enforcement experience and data roughly six to 12 months after the ordinance takes effect.

Supporters said the rules will provide a workable path to reduce the kind of steady low-frequency noise that standard A-weighted metrics do not capture. Opponents said the change weakens technical octave-band limits recommended by the consultants and the citizen advisory group, and complained the board advanced the vote while the Gainesville seat remained vacant.

The measure passed 5–2; Supervisors Victor Angry and Marta Jefferson voted no. County staff will begin hiring technical enforcement personnel and procuring meters during the implementation window and will present an enforcement-and-data report to the board after the first months of operation.