Arlington County, VA · Arlington County Zoning Ordinance (ACZO)
R-20 is Arlington County's largest-lot one-family residential district (ACZO §5.2), requiring a minimum lot area of 20,000 square feet and a minimum average lot width of 100 feet. Height is limited to 35 feet. It is the county's lowest-density residential designation, preserving large-lot single-family neighborhoods.
Development standards in R-20
Minimum lot size
20000 sq ft
Front setback
25 ft
Side setback
10 ft
Rear setback
25 ft
Read from Arlington County Zoning Ordinance (ACZO), effective through 2026-06-13.
Permitted uses in R-20
AllowedOne-Family Detached Dwelling
AllowedReligious Institution Church, mosque, synagogue, or temple, by-right (ACZO §5.1.2)
AllowedRecovery Residence By-right, subject to §12.3.9 use standards
AllowedAccessory Dwelling Unit By-right with administrative permit (ACZO §12.9.2)
AllowedHome Occupation By-right, subject to §12.9.11 standards
ConditionalChild Care Center / Day Care Special exception / use permit (ACZO §12.4.1)
ConditionalSchool (Elementary/Middle/High) Special exception / use permit (ACZO §12.4.1)
ConditionalCollege or University Special exception / use permit (ACZO §5.1.2)
ConditionalCommunity Center or Library Special exception / use permit (ACZO §5.1.2)
ConditionalHospital Special exception / use permit (ACZO §12.4.2)
ConditionalPark, Playground, or Playfield Special exception / use permit (ACZO §5.1.2)
ConditionalBed & Breakfast Special exception / use permit (ACZO §12.5.3)
ConditionalMembership Club or Lodge Special exception / use permit (ACZO §12.5.13)
ConditionalGroup Home / Dormitory Special exception / use permit (ACZO §12.3.3, §12.3.6)
ConditionalOpen-Air Market (Retail Sales) Use permit; the County Board sets conditions at use permit approval, and no open-air market may be within 1,000 feet of another (ACZO §12.5.17). U in all eight R districts in the §12.5 retail sales use table.
AllowedMedical or Dental Office in an Existing One-Family Dwelling By-right on a transitional site in an existing one-family detached dwelling, provided the residential character of the dwelling is not changed (ACZO §12.8.3.A).
AllowedSTR - Short-Term Rentals By-right (P) in the ACZO accessory use tables, subject to an accessory homestay permit issued by the zoning administrator (ACZO §12.9.12). Host must be the primary resident and present during the guest stay. Entire-home rentals (host absent) are not permitted.
Not AllowedMedical or Dental Office/Clinic Not permitted as a general use: the §12.5.16 row is blank for this district in the ACZO R-district use table, whose key reads 'Blank cell = not permitted'. A medical or dental office is separately permitted by-right in an EXISTING one-family detached dwelling on a transitional site (ACZO §12.8.3.A).
"Conditional" means the use generally requires a public hearing or special-exception approval — a very different timeline and risk profile from a by-right permit.
This is the zone. What about the parcel?
Zone rules are the starting point — the answer for a specific property also depends on lot
size, overlays, existing improvements and site conditions. Run a free address lookup to see
what applies to one property.
Standards as recorded by ZoneScore: Arlington County Zoning Ordinance (ACZO), Effective June 13, 2026
Values are read from the Arlington County Zoning Ordinance (ACZO). Where a district allows more density through site plan approval than by right, both are shown -- they are very different entitlement paths.