Airport Impact Overlay District Update

News and Announcements


The Airport Impact Overlay District indicates where airplane noise is anticipated to affect residential, school and commercial buildings. The current overlay district was implemented by the Board of Supervisors in the early 1990s to both prevent residential development in areas that would be affected by aircraft noise and mitigate impacts to prospective homebuyers. 

The Metropolitan Washington Airports Authority updated the noise exposure maps for Dulles Airport in 2019. The update reflects changes in the aviation environment in the last 30 years and prepares for future changes in airport usage. Based on the airport's updated noise contours, Loudoun County is amending its 2019 Comprehensive Plan to update policies related to the Airport Impact Overlay District (AIOD). The proposed amendments potentially affect more than 50,000 property owners around and near Dulles Airport. 

The Federal Aviation Administration has established the Day-Night Average Sound Level (DNL or Ldn) as a measure of community noise; this measure calculates the average noise level over a 24-hour period. Three tiers of noise are currently included in Loudoun’s Airport Impact Overlay District:

  • Ldn 65 or Higher: Properties located within this area are closest to the airport. New residential development is not permitted in this area.
  • Ldn 60-65: Properties located within this area are closer to the airport. Any residential development in this area requires disclosures at the time of sale; acoustical treatments for new residential construction and new additions to existing residences; and an easement established prior to construction of a new residence granting the right of overflight in the airspace above the property.
  • One-Mile Buffer: Properties located within this area are farthest from the airport while still being located within the AIOD. This designation requires a disclosure notice to be included with each sale of residential property.

Proposed Changes to the AIOD

The current process is intended to update the boundaries of the overlay district based on updated maps of noise contours for Dulles International Airport. The currently adopted noise contours for the airport are based on a 1992 noise study. MWAA published an updated noise study in 2019 to reflect current airport operations and flight paths. No change is proposed for the Leesburg Executive Airport.

The county is also seeking to clarify the overlay district regulations. The proposed update would clarify that disclosures of the AIOD areas for a property are required for each sale of a home within the overlay district, not just the initial sale. The proposed update also clarifies that changes to the boundaries do not invalidate previously approved residential rezonings.

How to Provide Public Input on the Proposed Changes to the AIOD

Members of the public may provide comments on the proposed changes in several ways:

Contact Information

Questions about how the proposed amendments may affect your property can be addressed to the Department of Planning and Zoning through email or by phone at 703-777-0246, option 5.

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