Overlay Districts

Creating an overlay district is a process by which local governments create specific land uses within established boundaries or criteria. DAAR believes overlay districts can be beneficial if used in either a market or environmental protection purpose, so long as the associated regulations:

1) are implemented to fix an actual problem;
2) property owners are notified directly;
3) are understandable to property owners;
4) do not diminish the value of the properties; and
5) do not have an adverse financial impact on existing property owners.

Property owners must be aware that if overlay districts are used to regulate land use without their notice or agreement, their private property rights and ability to use their land as they see fit may be compromised.

DAAR Recommendations

Examine Protection Alternatives

  • Given the significant impact overlay district regulations measures may have on property owners, businesses and the local economy, it’s critical to consider the least onerous but effective alternatives to protect certain land and water resources.

Weigh Costs and Benefits to County

  • Consideration of the most cost-effective methods and practices to overlay district regulations should be made. Due to the potential financial impact on existing property owners, the County should proceed with caution and gather the necessary information that allows a thorough examination of the impact the overlay district regulations will have on property owners. The County should also share the costs and benefits of their proposed actions with the public.

Direct Notice

  • In an effort to raise awareness about proposed overlay districts, DAAR encourages localities to provide direct proper notice to property owners, raise awareness about the potential impact and specific costs of implementing overlay district regulations on property owners and provide an open forum opportunity for property owners to understand the impact.


Overlays often are created for environmental purposes to protect a water or land resource from further development. Over the years there have been a number of overlay districts established upon lands in Loudoun County to help meet specific goals related to airport noise, quarries, historic preservation and mountain erosion. Some examples of Loudoun County Overlay Districts include the Airport Impact Overlay District, Floodplain Overlay District, Historic Districts and Limestone Overlay Districts.


Loudoun County manages development on the mountainsides through a Mountainside Development Overlay District (MDOD) that contains land use restrictions and performance standards to minimize the destruction of individual resources and the disturbance of the ecological balance of these resources.

Steep slopes and moderately steep slopes occupy an area of approximately 50,000 acres in the county. If improper land use and disturbance occurs, these areas could experience erosion, building or road failure, and contribute to downstream flooding, as well as other health and safety hazards.

The Village Conservation Overlay District (VCOD) layer is a zoning overlay district and identifies thirteen small villages and hamlets outside of the boundaries of Loudoun County’s incorporated towns and planned residential communities that contain unique, scenic and historic characteristics that should be maintained and protected.

The Limestone Overlay District covers the northeastern portion of the county and includes approximately 18,000 acres. The overlay district is designed to protect residents from sinkholes and groundwater contamination caused by limestone.

The Airport Impact Overlay District uses Dulles International aircraft noise contours, calculated for a full-build-5-runway layout, imposes development restrictions within specified areas.

Many properties within the Rural Historic Villages of Aldie, Bluemont, Lincoln, Taylorstown and Waterford are located within County Historic and Cultural Conservation Districts which are zoning overlays that regulate the appearance of properties through architectural design guidelines.

The Floodplain Overlay District is a mapped zoning area composed of Major Floodplain and Minor Floodplain. The county’s Major Floodplain is based on the “Special Flood Hazard Area” shown on FEMA’s Flood Insurance Rate Map for Loudoun County. The map also shows the county’s Minor Floodplain, which continues upstream from the Major Floodplain. The types of activities and land uses in floodplain are restricted or prohibited by federal and local regulations.

Our Focus

Advocate that any proposed regulation associated with overlay districts be made in proportion to the need or the effect on sensitive land and water resources.