ADU Rules in Portsmouth, Virginia

Portsmouth is an independent city in Hampton Roads with approximately 100,000 residents. As an independent city, Portsmouth operates completely separately from any surrounding county and handles all local government functions independently. The city sits on the western bank of the Elizabeth River, directly across from Norfolk, and is connected to Norfolk by the Midtown and Downtown tunnels. Portsmouth's identity is inseparable from the Portsmouth Naval Shipyard (officially called Norfolk Naval Shipyard, despite being physically in Portsmouth) — the oldest and one of the largest naval shipyards in the United States, established in 1767.

Portsmouth has a rich stock of historic residential neighborhoods, including the Olde Towne historic district, and a significant amount of pre-WWII housing that can be well-suited for ADU conversions.

Virginia statewide ADU law status

Virginia has no enacted statewide ADU preemption: SB 304 of 2024 would have required ADUs by-right but was deferred to the Virginia Housing Commission and not enacted. Va. Code § 15.2-2292.1 governs only temporary family health-care structures (≤300 sq ft caregiver units), not general ADUs.

Portsmouth Local Zoning for ADUs

Portsmouth's zoning ordinance establishes residential districts with varying density. Typical ADU standards in single-family zones:

• Maximum size: Generally limited to 1,200 square feet or a percentage of the primary dwelling floor area
• Unit count: One ADU per single-family lot
• Types: Detached (new rear-yard structure), attached (addition), or internal (basement/attic/garage conversion)
• Setbacks: Detached ADUs must meet the applicable district's rear and side setbacks
• Height: Detached ADUs are typically limited to one story or 16 feet
• Lot coverage: Combined structures must not exceed the district maximum
• Utilities: City water and sewer connection required where available

Contact the Portsmouth Department of Planning at (757) 393-8836 or visit portsmouthva.gov/162/Planning for the current ordinance provisions and any recent amendments.

Norfolk Naval Shipyard — AICUZ and Industrial Considerations

The Portsmouth Naval Shipyard (Norfolk Naval Shipyard) is an industrial naval facility — not an airfield — and does not have an AICUZ in the same way that air stations do. However:

• Naval Station Norfolk across the Elizabeth River has associated AICUZ noise contours that can extend into western Portsmouth depending on flight patterns
• The shipyard area itself generates noise, industrial activity, and potentially environmental considerations that may affect nearby residential areas
• Some Portsmouth neighborhoods near the shipyard may have deed restrictions, easements, or land use agreements that affect development

Verify with the Portsmouth Planning Department whether your specific parcel is affected by any military-related overlay or encumbrance.

Flooding and Sea Level Rise — Critical for Portsmouth

Portsmouth is one of the most flood-vulnerable cities in Hampton Roads, and Hampton Roads is one of the most flood-vulnerable regions in the United States. The city is low-lying, with the Elizabeth River and its tributaries creating extensive flood-prone areas. Relative sea level rise in Hampton Roads — driven by global sea level rise and land subsidence — exceeds 14 inches over the past century. Portsmouth has experienced significant tidal flooding and storm surge flooding historically.

For ADU construction:

• Properties in FEMA Special Flood Hazard Areas (Zone AE or VE) must build new structures at or above the Base Flood Elevation (BFE)
• Basement ADUs in flood zones are extremely problematic and may not be permitted
• Elevated ADUs — on piers or above a garage — are often more feasible in flood-prone areas
• Mechanical systems (HVAC, electrical panels) must be elevated above BFE
• FEMA is updating Hampton Roads flood maps; consult the city's floodplain administrator for the most current data

Portsmouth has a Floodplain Management Program; contact the city to identify your BFE and any local floodplain regulations that exceed FEMA minimums.

Olde Towne Historic District

Portsmouth's Olde Towne historic district is one of the largest and best-preserved urban historic districts in Virginia, with architecture spanning from the colonial period through the Victorian era. Olde Towne is both a nationally listed historic district and locally designated, with architectural review requirements:

• Exterior modifications to buildings in Olde Towne require review by the Architectural Review Board (or equivalent body)
• New detached structures in rear yards of historic properties may require design compatibility review
• Interior ADUs (basement or attic conversions) with no exterior changes are generally not subject to architectural review
• The historic review process adds time; plan accordingly

Permitting Process

1. Confirm zoning district and overlays — Verify on the city GIS or contact Planning
2. Check historic district status — Determine if your property is in Olde Towne or another historic overlay
3. Flood zone check — Verify FEMA flood zone and BFE at msc.fema.gov
4. Pre-application consultation — Portsmouth Department of Planning, (757) 393-8836
5. Building permit application — Submit to the Building Inspections division
6. Architectural review (if in historic district)
7. Inspections and Certificate of Occupancy — Required before occupancy

Contact Information

• Portsmouth Department of Planning: (757) 393-8836 | portsmouthva.gov/162/Planning
• Building Inspections: (757) 393-8596
• Municipal Code: library.municode.com/va/portsmouth/codes/code_of_ordinances

Disclaimer: This guide provides general information only and is not legal or planning advice. Zoning regulations, historic district boundaries, and flood maps change over time. Always verify current requirements directly with the City of Portsmouth Planning Department and the official municipal code before making any development decisions.