Can you build an ADU in Alexandria City?
Alexandria is the most permissive jurisdiction in Northern Virginia for this. A separate building in the backyard is allowed outright, it can sit as close as a foot from your side or rear line, no extra parking is required, and you do not have to live on the property. You do not have to wait for July 2027. Check first that you are actually in the City — a great many "Alexandria" addresses are in Fairfax County, which is stricter.
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Can you build one?
Allowed without a special permit or hearing. An accessory dwelling is a permitted accessory use, so there is no special permit and no hearing — you build to the standards and apply for the usual building permits. It is allowed alongside a single-unit, two-unit or townhouse dwelling, which is unusually broad; most jurisdictions restrict this to detached houses. One per recorded lot. The kitchen has to be a real one: a sink, a cooking appliance, a food preparation counter, storage cabinets and a refrigerator.
§ 7-101(N); § 7-203(B)(1), (2), (4)Read the sectionRead at source Sep 12, 2026How big can it be — Inside your existing house?
Up to 33% of your house’s floor area. Up to one third of the house’s gross floor area.
§ 7-203(B)(3)Read the sectionRead at source Sep 12, 2026How big can it be — A separate building, on a lot larger than 2,500 sq ft?
Up to 500 sq ft, or 33% of your house’s first floor area — whichever is larger. Whichever is larger — one of the few rules anywhere that works in your favor. Measured on the FIRST FLOOR of the accessory building and of the house, not gross floor area, so a second story is not counted the same way.
§ 7-203(C)(1)Read the sectionRead at source Sep 12, 2026How big can it be — A separate building, on a lot of 2,500 sq ft or less?
Up to 350 sq ft, or 33% of your house’s first floor area — whichever is larger.
§ 7-203(C)(1)Read the sectionRead at source Sep 12, 2026How far from the property line?
Unusually generous, and tiered by height. A separate building may sit as little as one foot from your side and rear lot lines. Three feet if the wall facing that line has windows or doors. Any part of it between 13.5 and 16 feet tall needs 2.5 feet, and anything over 16 feet needs five. A lower figure applies if your zone requires one.
§ 7-203(C)(3)Read the sectionRead at source Sep 12, 2026Do you have to live there?
No. You do not have to live there. The ordinance requires only that the two dwellings stay under common ownership — you cannot sell the accessory unit separately — which is a different thing from an owner-occupancy rule. Fairfax and Arlington both require you to occupy one of the units; Alexandria does not.
§ 7-203(B)(5)Read the sectionRead at source Sep 12, 2026Do you need more parking?
No extra spaces required. No off-street parking is required for an accessory dwelling. The ordinance exempts it outright, which is the most permissive position of any jurisdiction we cover.
§ 7-203(D)Read the sectionRead at source Sep 12, 2026What does the permit cost?
Not yet researched. Building permit and plan review fees will apply; the City publishes a fee schedule that still needs reading before we state a figure.
Which kinds are allowed?
All four routes are open. The ordinance sets separate bulk rules for a detached building precisely because it expects them to be built, and unlike Fairfax there is no minimum lot size gating it.
§ 7-203(C)Read the sectionRead at source Sep 12, 2026The rules are being rewritten right now
The City has amended this section repeatedly, most recently in June 2025, and adopted its current ADU policy in January 2021. Because that predates 1 January 2026, Va. Code § 15.2-2292.4(I) may exclude Alexandria from the 2027 statewide law — though in Alexandria’s case that matters less, since the local rules are already more generous than the state minimum.
Ord. No. 5593, § 5, 14 June 2025Read the sectionRead at source Sep 12, 2026If you’re in an HOA
The state law does not override your HOA. Check your deed and closing paperwork for a recorded declaration of covenants, or look the property up in the City land records. Condominium and townhouse communities are common in Alexandria, and their instruments can prohibit this regardless of what the City allows.
Va. Code § 15.2-2292.4(F)Read the sectionRead at source Sep 12, 2026Every rule on this page links to the section of the Alexandria City ordinance it comes from, so you can read it yourself. Localities are amending these rules ahead of July 1, 2027 — worth confirming the section before you commit money to a design. This is general information about Alexandria City, not a determination about your particular lot.
What does this mean for your lot?
Three questions. We’ll check the Alexandria City rules against your situation and tell you what you’re actually looking at — including if the answer is no.