Nashville Is Making It Easier to Build Detached Accessory Dwelling Units (DADUs)
- Fabl Design Communications
- 11 minutes ago
- 4 min read
Nashville has taken a major step toward expanding housing options—without dramatically changing neighborhood character.
A newly adopted ordinance updates Metro’s zoning code to simplify, expand, and clarify the rules around Detached Accessory Dwelling Units (DADUs). These changes affect homeowners, builders, and designers across both the Urban Services District (USD) and parts of the General Services District (GSD).
Here’s what’s changing—and why it matters.
Why This Matters
For years, DADUs in Nashville have been allowed only under narrow conditions—often requiring special overlays, large lot sizes, or alley access. This ordinance recognizes that:
Homeowners want flexible housing options for family, aging parents, or long-term rental income
The city needs more housing, but in a context-sensitive way
Clearer rules make permitting faster and more predictable
The result is a zoning update that allows gentle density while maintaining neighborhood scale and character.
Big Picture Changes at a Glance
1. DADUs Are Now a Base Zoning Allowance (Not Just an Overlay)
Previously, many properties required a DADU Overlay District to allow a detached unit. Under the new rules:
DADUs are permitted by base zoning in many residential districts within the Urban Services District
The overlay is now mainly used to expand DADU eligibility in parts of the General Services District (GSD)
This simplifies approvals and creates more consistent rules across the county.
2. More Lots Are Eligible
The ordinance removes several long-standing barriers, including:
❌ Minimum 15,000 sq ft lot size
❌ Mandatory alley access
❌ Location inside a historic or urban design overlay
As long as a lot meets zoning standards and design requirements, a DADU may now be possible where it wasn’t before.
3. Larger DADUs Are Now Allowed
The maximum size of a DADU has increased:
Up to 850 sq ft on lots smaller than 10,000 sq ft
Up to 1,200 sq ft on lots 10,000 sq ft or larger
Previously, DADUs were capped at 700 sq ft on all lots.
The key requirement remains:👉 The DADU must still be clearly subordinate in size, height, and mass to the primary home.
4. Clearer Height and Massing Rules
To maintain neighborhood compatibility, the ordinance reinforces proportional design:
DADU height cannot exceed the eave height of the main house
Maximum eave heights:
10 ft for one-story DADUs
17 ft for two-story DADUs
Maximum roof ridge height: 27 ft, measured from average finished grade
These standards help ensure DADUs feel like part of the property—not a second primary house.
5. Accessory Structures Get More Flexibility Too
The ordinance also updates rules for garages, workshops, and other accessory buildings:
Accessory structures can now cover:
850 sq ft, or
50% of the main house footprint (whichever is greater)
With an absolute max of 2,500 sq ft
Smaller accessory buildings (≤ 850 sq ft) may have reduced side and rear setbacks, making design more flexible on tighter lots
This is a meaningful change for homeowners planning garages with apartments above, studios, or future DADUs.
6. Owner Occupancy Is Still Required
To prevent speculative use:
Only one DADU per lot is allowed
The DADU cannot be separately sold
One of the two dwellings must be owner-occupied
Additionally:
🚫 Short-term rentals (Airbnb/STRP-Owner Occupied) are not allowed in DADUs built or converted under this ordinance on single-family, Residential Neighborhood, or Residential Limited lots.
7. Expansion into the General Services District (GSD)
Homeowners outside the Urban Services District now have a new option:
A DADU Overlay District may be applied in parts of the GSD
This includes zoning districts like AR2a, AG, R, and RS
Existing DADU overlays remain valid until formally removed by Council
This change gives rural and semi-rural homeowners more flexibility while still requiring an intentional zoning process.
What This Means for Homeowners and Builders
If you’ve been considering a DADU in Nashville, this ordinance:
Makes approvals more predictable
Allows better-sized, more functional units
Expands eligibility to more properties
Maintains neighborhood scale and character
That said, DADUs are still highly regulated—setbacks, design compatibility, utilities, parking, and ownership rules all matter.
Thinking About a DADU?
Whether you’re exploring housing for family, long-term rental income, or future flexibility, the first step is understanding what your lot can actually support under the updated code.
At Fabl Design, we help homeowners and builders navigate:
Zoning feasibility
Lot constraints
DADU design that complies and feels intentional
Permit-ready plans that reflect real-world construction
If you’re curious whether a DADU makes sense for your property, we’re always happy to talk through it.
Disclosure
The information provided in this blog post is intended for general informational purposes only. While every effort has been made to ensure the accuracy and completeness of the content, zoning regulations are subject to change, and their interpretation may vary. Therefore, this post may not capture all nuances or recent updates.
Readers are advised to consult the Metropolitan Government of Nashville and Davidson County’s official zoning documentation or contact local zoning authorities for the most current and detailed information specific to their property or project. The author assumes no responsibility for any errors or omissions or for actions taken based on the information provided herein.
Resources
