Alabama ADU Laws

Complete 2026 guide to accessory dwelling unit regulations

○Local Control Only

📋Quick Facts

Max Size
1,000 sq ft
Size Limit
40% of primary
Owner Occupancy
May be required
Parking
Set locally
Approval Process
Varies locally

⚠️Key Requirements & Restrictions

  • •No statewide ADU law - Alabama lacks statewide building code
  • •Entirely local control - each county/municipality sets own rules
  • •Mobile County: Ordinance 64‑17/64‑26 (June 2022) allows ADUs by right in R-1/R-2 zones
  • •Most counties allow ADUs through IRC provisions or case-by-case approval
  • •Rules vary dramatically by municipality

📖Detailed Analysis

No statewide ADU law - Alabama's lack of statewide building code means ADU regulations are entirely managed locally. Mobile County has comprehensive ADU regulations (Ordinance 64‑17/64‑26, June 2022) allowing ADUs in R-1/R-2 zones with size limit of 800-1,000 sqft or 40% of primary structure, architectural matching required, one parking space, no separate sale/short-term rental. Most counties allow ADUs through IRC provisions or case-by-case zoning approval. Rural areas generally more permissive than urban areas. Jefferson County (Birmingham) has strict 200 sqft maximum. Baldwin County allows up to 1,200 sqft (60% of primary). Process typically requires building permit, health department approval for septic, and 911 addressing. No statewide grants but some local fee waivers available.

🔗Official Resources

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⚠️ Disclaimer

The information provided on this website is for general informational purposes only and does not constitute legal, financial, or professional advice. ADU laws, regulations, and requirements vary by jurisdiction and change frequently. While we strive to keep this information accurate and up-to-date, we make no representations or warranties of any kind about the completeness, accuracy, reliability, or suitability of this information. Always consult with qualified local professionals, including attorneys, architects, and your local planning department, before making any decisions regarding ADU construction or investment. Use of this information is at your own risk.

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Last updated: February 2026