Building an Accessory Dwelling Unit (ADU) in Anne Arundel County, MD: Your Complete Guide

Thinking about building an Accessory Dwelling Unit (ADU) in Anne Arundel County, MD? Thanks to Bill 6-23, the county has made it easier for homeowners to add ADUs to their properties. Whether you want a rental apartment, in-law suite, home office, or guest house, this guide covers everything from zoning laws and costs to design trends and rental potential.

🏡 What Is an ADU?

An Accessory Dwelling Unit (ADU) is a fully independent living space located on the same lot as a primary single-family home.

Common ADU Types

• Detached ADU – A separate backyard structure (e.g., a cottage or “tiny house”).
• Attached ADU – A home addition with its own entrance.
• Garage Conversion – Converting an existing garage into a code-compliant apartment.
• Basement Apartment – Finishing a basement with a private entrance, kitchen, and bath.

✅ Are ADUs Legal in Anne Arundel County?

Yes! Anne Arundel County officially allows ADUs on residential properties. Thanks to Bill 6-23, many previous barriers—like minimum lot size requirements—have been removed.

📌 Key Requirements

• 🏗️ A building permit is required.
• 📏 ADUs must meet zoning & building codes.
• 🏡 **Short-term rental rules apply** – The owner must reside in one of the units.

Pro Tip: If you live in City of Annapolis, other cities with zoning departments, or a community with an HOA, check local or HOA guidelines for additional restrictions.

📜 Anne Arundel County ADU Zoning Rules

Below are the most important ADU regulations in Anne Arundel County. For full details, visit the County Code of Ordinances or Department of Inspections & Permits.

• One ADU Per Lot
  • You can only have one Accessory Dwelling Unit on a single-family residential lot.
• No Minimum Lot Size
  • Bill 6-23 removed the old lot-size requirement; smaller lots may now qualify.
• ADU Size Limits
  • Detached ADU: Maximum of 800 sq. ft. or 50% of the main dwelling’s size (whichever is less).
  • Attached/Internal: Must be smaller than the principal home; check code specifics for attached additions.
• Permit Required
  • A standard building permit is mandatory. Submit architectural plans and undergo inspections for plumbing, electrical, and structural compliance.
• Setbacks
  • Detached ADUs must follow accessory structure setback rules (distances from property lines vary by zone).
• No Extra Parking Required
  • The county no longer requires an additional parking space for ADU occupants. Still, plan parking wisely to avoid congestion.
• Owner Occupancy & Rentals
  • Long-Term Rentals: No requirement for the owner to live on site.
  • Short-Term Rentals (Airbnb/VRBO): The owner must reside in either the primary home or the ADU if the other unit is rented short-term.
• Separate Entrance & Address
  • The ADU must have its own entry. It typically shares the main property address with a “Unit B” designation.

💰 How Much Does It Cost to Build an ADU?

Costs vary based on size, design, and finishes. Below are typical estimates for Anne Arundel County.

💡 Cost Factors

• 🔧 Construction Materials & Finishes – Higher-end finishes increase costs.
• 💡 Utilities & Permits – Electrical, plumbing, and HVAC add expenses.
• 🏗️ Labor & Custom Design – Hiring contractors raises the budget.

✅ Good News: Bill 6-23 **waives impact fees** for ADUs added to existing homes, saving homeowners $5,000–$20,000.

🏠 Best Uses for an ADU in Anne Arundel County

• 💰 Rental Income – Earn around $1,800 – $2,000+ per month renting out a well-located ADU, offsetting your mortgage or generating extra cash flow.
• 👵 In-Law Suite – Provide a private residence for aging parents or extended family while keeping everyone close.
• 💼 Home Office or Studio – Separate work from home life in a dedicated workspace, or craft a music/art studio with minimal distractions.
• 🏡 Guest House – Create a welcoming retreat for visitors or out-of-town relatives who prefer privacy.
• 🎓 Student Housing – With Anne Arundel Community College and the U.S. Naval Academy nearby, an ADU can cater to students or military families in need of short-term accommodation.

✅ ROI Tip: ADUs in waterfront areas (e.g., near Annapolis) may command higher rents or premium Airbnb rates, offering a strong long-term investment.

📐 Design Trends for ADUs in Anne Arundel County

1. Open-Concept Layouts
   • Make smaller spaces feel larger by combining living, kitchen, and dining areas.
2. Smart Home Features
   • Add voice-activated lighting or thermostat controls for a modern touch.
3. Sustainable Materials
   • Consider energy-efficient insulation, solar panels, or on-demand water heaters for lower utility costs.
4. Outdoor Living Areas
   • A private deck or patio can enhance the ADU’s appeal—especially in scenic communities.
5. Multi-Functional Furniture
   • Murphy beds, built-in storage, and foldable furniture maximize flexibility in compact units.

📌 Helpful Anne Arundel County Links

• 📜 Bill 6-23 – ADU Legislation
• 📖 Anne Arundel County Code of Ordinances
• 🏗️ Department of Inspections & Permits

🔎 Thinking about an ADU? Now is the perfect time! Reach out to Gabriel Maggio Construction, experts in Anne Arundel County’s ADU regulations, permitting, and high-quality craftsmanship. Let us help bring your ADU vision to life!

📢 Disclaimer: This article is for informational purposes only. Always verify ADU regulations with Anne Arundel County before proceeding with construction.