Manassas

The City of Manassas permits accessory dwelling units as a supplementary use to single-family detached dwellings in the city's primary residential districts under its zoning ordinance. The framework follows the typical Northern Virginia suburban pattern with one defining local feature — the Manassas Regional Airport (HEF) influence area covers a meaningful share of the city's residential acreage and adds airport-disclosure, noise-attenuation construction standards, and avigation-easement requirements on top of standard zoning compliance. Common Manassas ADU standards: one ADU per parcel; the ADU must be clearly accessory and subordinate to a principal single-family dwelling; a base size cap typically in the 750-900 square-foot range applicable across the city's residential districts; configuration options including attached, interior-conversion (basement apartment, attic conversion, attached garage conversion), and detached (subject to lot-size and setback feasibility on the city's typical 8,000-15,000 sq ft suburban residential lots); detached ADUs typically must meet principal-dwelling setbacks for the underlying district rather than reduced accessory-structure setbacks; the ADU cannot be subdivided off or sold separately from the principal dwelling; and family-relationship or owner-occupancy provisions may apply per current ordinance text. Because Virginia has no statewide ADU preemption (see state file stateAduLaw, citing Va. Code § 15.2-2280 et seq. as the local-zoning enabling statute), Manassas' ordinance is the authoritative regime on every parcel in the city — Prince William County's separate ADU ordinance does NOT apply within Manassas city limits despite the geographic enclosure. The principal binding constraint on a meaningful share of Manassas ADU projects is the Manassas Regional Airport noise / AICUZ-style influence area, which adds noise-attenuation construction requirements on parcels within the higher-noise contours and requires disclosure-and-avigation-easement provisions on a broader band of city parcels. Confirm the current ordinance text with the City of Manassas Department of Community Development before relying on a specific size threshold or configuration rule.

The City of Manassas administers an overlay portfolio with one structurally defining feature that distinguishes it from nearly every other Virginia independent city — the Manassas Regional Airport (HEF) airport-influence area, which covers a meaningful share of the city's southern and central residential acreage. Manassas Regional Airport is the largest general-aviation airport in Virginia by based-aircraft count and one of the busiest GA airports in the Mid-Atlantic, generating substantial aircraft-noise contours, FAA Part 77 imaginary-surface restrictions, and (in the higher-impact contours) AICUZ-style residential-intensification limits. Beyond the airport overlay, Manassas administers (1) the Manassas Historic Overlay District covering the Old Town Manassas downtown core (centered on Main Street, Battle Street, Center Street, and the historic Manassas train depot), (2) a Floodplain Overlay tied to FEMA-mapped Special Flood Hazard Areas along Flat Branch, Broad Run / Bull Run tributaries within city limits, and other minor drainage corridors, (3) viewshed and adjacency considerations relating to Manassas National Battlefield Park (the National Park Service unit in adjacent Prince William County, NOT within Manassas city limits despite the name), (4) standard Virginia statewide regulatory layers (Uniform Statewide Building Code, Erosion and Sediment Control program, Virginia Stormwater Management Program), and (5) urban-design considerations along the Sudley Road / Mathis Avenue / Centreville Road commercial corridors. Manassas is NOT a Chesapeake Bay Preservation Act Tidewater locality — the city sits well west of the Tidewater / Piedmont line, in the Piedmont physiographic province, with surface waters draining through the Occoquan / Potomac watershed to the Chesapeake Bay but without the CBPA RPA/RMA layer that constrains Tidewater jurisdictions. This is a substantial regulatory simplification compared to Hampton Roads or Northern Virginia Tidewater-line jurisdictions. Manassas also has no CalFire-equivalent WUI regime (Virginia has none), no seismic-retrofit overlay, and no inside-the-Beltway DC-adjacency Federal Triangle / National Capital Planning Commission viewshed entanglement (that constraint applies inside Arlington and Alexandria, not in Manassas).

• Manassas Regional Airport (HEF) influence area — noise contours, FAA Part 77 imaginary surfaces, AICUZ-style residential intensification limits
• Manassas Historic Overlay District (Old Town Manassas)
• Floodplain Overlay (Flat Branch, Broad Run / Bull Run tributaries, and minor drainage corridors)
• Manassas National Battlefield Park viewshed and adjacency (NPS unit in adjacent Prince William County)

The City of Manassas Department of Community Development and Building Inspections division jointly issue residential permits for every parcel in the city. There is no county-level alternative for any Manassas parcel because Manassas is an independent city — Prince William County (which surrounds Manassas) has NO zoning or permitting authority over Manassas parcels despite the geographic enclosure. An ADU permit bundle on a Manassas parcel typically includes: (1) a Zoning Compliance verification / Zoning Permit confirming the ADU meets supplementary-regulation standards (size cap, one-per-parcel, principal-dwelling setbacks, district eligibility, accessory-coverage limits, owner-occupancy or family-relationship terms if applicable); (2) airport-influence-area review for parcels within the Manassas Regional Airport noise contours, surface restrictions, or avigation-easement disclosure zone — this is a meaningful additional layer that does not exist in most Virginia cities; (3) Floodplain Development Permit if the parcel is within a FEMA Special Flood Hazard Area (most relevant for parcels along Flat Branch, Broad Run / Bull Run tributaries, and other minor drainages); (4) a Building Permit with stamped plans, including noise-attenuation construction details where airport-influence noise contours dictate; (5) trade permits for Electrical, Plumbing, and Mechanical filed by licensed Virginia contractors; and (6) connection coordination with City of Manassas Utilities for water, sewer, and (notably) electric service — Manassas' municipal electric utility means the city itself handles the new ADU's electric service rather than a regional investor-owned utility. The city is fully served by municipal water and sewer with no rural well-and-septic component within the city limits.