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Accessory Structures in Herndon, VA (2026)

3 verified accessory structures rules for Herndon, Virginia, sourced directly from the municipal code and official government pages.

Verified from official government sources

ADU Rules

Herndon permits accessory dwelling units (ADUs) in certain residential districts with a special exception or by right depending on zoning. ADUs must be subordinate to the primary dwelling, have a separate entrance, and comply with parking and owner-occupancy requirements. Virginia encourages but does not mandate ADU approval under VA Code §15.2-2292.1.

Accessory Structures: Adu Rules

Some Restrictions

Shed Rules

In Herndon, sheds 256 square feet or smaller and one story do not require a building permit under the Virginia USBC, but still must comply with zoning setbacks. Sheds over 256 sq ft require a building permit. All sheds must respect property lines, typically with minimum setbacks of 5 feet from side and rear lot lines, and comply with lot coverage limits and HOA rules.

Accessory Structures: Shed Permits

Some Restrictions

Garage Conversions

Converting a garage to living space in Herndon requires a building permit, compliance with the Virginia USBC for habitable space, and zoning review. Converted space must meet egress, ceiling height, ventilation, and insulation standards. Required off-street parking typically cannot be eliminated, so conversions often need replacement parking. HOA approval is commonly required.

Accessory Structures: Garage Conversions

Some Restrictions

Looking for Fairfax County county-wide rules?

County ordinances apply to unincorporated areas and may supplement Herndon city rules.

Accessory Structures in Fairfax County