Impervious Area
A surface composed of any material that significantly impedes or prevents natural infiltration of water into the soil. Impervious surfaces include, but are not limited to roofs, buildings, streets, parking areas, pools and any concrete, asphalt or compacted gravel surface.
Low Density Neighborhoods
Areas where homes are spaced further apart, and there is more open space compared to high-density areas. These neighborhoods often feature:
- Single-family homes: Most of the residences are individual houses rather than apartments or multi-family units.
- Larger lots: Homes are built on larger plots of land, providing more space for yards and gardens.
- Zoning regulations: These areas are often zoned to limit the number of homes per acre, ensuring a less crowded environment.
- Impervious surfaces: These neighborhoods have a significant amount of impervious surfaces like buildings, driveways, walkways, and patios, which impact stormwater management and tree canopy dynamics.
In Arlington County, low-density residential areas are primarily zoned R5-20, representing about 70% of the private land. These zones are where impervious surfaces are increasing the most, affecting stormwater and tree impacts
Lot Coverage
Arlington’s Zoning Ordinance requires lots with one- and two-family dwellings to limit the maximum coverage of their lot to a specific percentage of the lot's total area. The maximum coverage limit for a given lot is determined by:
- The lot’s zoning district classification;
- Presence of a detached garage; and
- Whether the dwelling has a front porch of at least 60 square feet.
The lot coverage limits include maximum requirements for the size of a main building footprint, measured in square feet. Main building footprints must adhere to separate, but inclusive, maximum coverage percentages.
Read more about how lot coverage requirements are calculated.