Fairfax County, VA Data Centers & Crypto Mining: Data Center Noise Limits (2026)
Key Facts
- Night Limit
- 55 dBA at residential (10pm-7am)
- Day Limit
- 60 dBA at residential
- Measurement
- At property boundary, ANSI Type 2
- Noise Studies
- Pre- and post-construction required
- Penalty
- Class 2 misdemeanor, $1,000
Summary
Fairfax County caps continuous data center noise at the property line: 55 dBA at night (10 p.m.-7 a.m.) and 60 dBA daytime where it reaches residential property. Every data center must pass pre- and post-construction noise studies proving compliance with Noise Ordinance Chapter 108.1.
no person shall permit, operate, or cause any source of sound or sound generation to create a sound which exceeds the limits set forth in the following table titled "Maximum Sound Levels" when measured at the property boundary of the sound source or at any point within any other property affected by the sound. ... Residential Areas ... 7 a.m. to 10 p.m. 60 ... 10 p.m. to 7 a.m. 55.
Full Breakdown
Under Noise Ordinance subsection 108.1-4-2, continuous sound measured at the property boundary may not exceed 55 dBA overnight (10 p.m.-7 a.m.) or 60 dBA daytime at residential property, 65 dBA in commercial districts, and 72 dBA day / 65 dBA night in industrial districts. Sound reaching an affected residential lot is judged against that lot's 55/60 dBA limit. Zoning subsection 4102.6.A(6) also requires a noise study before site plan approval and a post-construction study before a Nonresidential Use Permit, each proving compliance to the Zoning Administrator. Modeling must assume worst-case operation with all cooling equipment at full load. Routine back-up generator testing is limited to 7 a.m.-9 p.m., two hours per day.
Violations & Fines
Exceeding the Chapter 108.1 limits is a Class 2 misdemeanor, up to six months in jail and a $1,000 fine; the civil-penalty option does not apply to industrially zoned business noise. A failed post-construction study blocks the use permit.
Frequently Asked Questions
How loud can a Fairfax County data center be?
Do data centers have to prove they will be quiet?
Sources & Official References
Other rules in Fairfax County
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