Everything homeowners ask about building an ADU in Arlington — answered with 2026 data.
Yes, ADUs are allowed in Single-family residential zones in Arlington, VA. The maximum size for a detached ADU is 1,000 sq ft. Attached ADUs can be up to 850 sq ft. Arlington has an ADU-friendliness score of 7/10. Check our full Arlington ADU rules page for complete zoning details.
ADU construction in Arlington typically costs $170,000-$340,000. The cost per square foot averages $170-$340. Garage conversions are more affordable at $90,000-$200,000, while prefab ADUs cost $130,000-$290,000. Permit fees add $2,800-$4,500 to your budget. See our detailed Arlington ADU cost guide.
Detached ADUs in Arlington can be up to 1,000 sq ft. Attached ADUs are limited to 850 sq ft. Junior ADUs (JADUs) have a cap of Not allowed. Maximum height is 25 ft for detached ADUs (updated 2026); 35 ft for primary structures. You are allowed up to 1 ADU per lot on a qualifying lot.
Rear setback: 5 ft (interior lots); 10 ft (corner lots). Side setback: 3 feet. Front setback: 20 feet. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
1 space per unit. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required. Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Arlington is typically 50-75 days. The plan check process takes approximately 2-3 weeks. Pre-approved plans availability: Available.
Average ADU rental income in Arlington: 1-bedroom units rent for $1,700-$2,200/mo/month, 2-bedroom units for $2,100-$3,000/mo/month. Short-term rentals: Not permitted. Expected ROI: 5-7% annual return.
The minimum lot size for an ADU in Arlington is 4,000 sq ft. This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Arlington, a garage conversion typically costs $90,000-$200,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.