Data centers seeking a Loudoun rezoning must now study their noise on homes and schools within 500 feet and say which substations will serve them.

Companies that want Loudoun County to rezone land for a large data center now have to show how loud it will be at the nearest homes and schools. They also have to say which power substations will serve it.

The county announced the new paperwork in a news release on Friday. It comes from a Virginia law passed in the 2026 General Assembly session, Section 15.2-2209.5 of the state code.

Who it covers

The law calls these projects high energy use facilities. That is any facility the applicant expects to need 100 megawatts or more from a retail electric utility. In Loudoun, the county said, data centers are the most common example.

The rules apply to rezoning, special exception and special use permit applications. The county said they cover all current and future applications of that kind.

What applicants must now file

The county’s one-page checklist asks for:

  • a sworn affidavit and the applicant’s correspondence with the electric utility, showing the power and voltage the site will need at full build-out
  • a sound profile of the facility on homes and schools within 500 feet of its property line
  • its effect on ground and surface water, farmland, parks, registered historic sites and forest on or next to the site
  • a form from the utility naming any new or existing substations that will serve it, and the transmission voltage it will need

The state law makes the noise study mandatory. The water, farmland, parks, historic sites and forest review is optional under the law. Loudoun has chosen to require it, the county said.

The Planning Commission and the Board of Supervisors may use the documents to judge a project against the county’s Comprehensive Plan, its noise ordinance and its Zoning Ordinance.

What it does not cover

  • By-right projects. Sites that can build a data center without a board vote, through administrative approval, are not covered, the county said.
  • Smaller expansions. The law does not apply to an already approved site that is expanding, as long as the expansion adds less than 100 megawatts.

Since March 2025, every new data center application in Loudoun has needed a special exception from the Board of Supervisors. So new data center proposals go through a board vote, and now through this checklist too.

The pause vote is Nov. 17

The board is also weighing a pause of up to 12 months on data center and substation applications that need its approval. That item was moved from Oct. 20 to the board’s Nov. 17 meeting, the county said in an Oct. 20 notice. A wider review of the county’s data center standards is expected to wrap up in summer 2027.

The pause is separate from this week’s preliminary deal with Amazon that would keep data centers off the former George Washington University campus in Ashburn.

What it means for you

If you live near land where a data center is proposed, the application file should now include a study of the noise at homes and schools within 500 feet. It should also name the substations that would serve the project and the transmission voltage it needs.

Applications and their documents are posted through the county’s legislative land use page. How zoning cases work locally is on our building permits and zoning page. To speak at the Nov. 17 board meeting, sign up at loudoun.gov/SignUpToSpeak.