Published August 28, 2026
Saint Paul permits accessory dwelling units in most residential zoning districts — interior, attached, and detached. Combined with the city's older, larger-lot housing stock and its active rental licensing program, that makes Saint Paul one of the more workable ADU markets in Minnesota.
Confirm these with Saint Paul DSI before designing
- Whether your zoning district permits an ADU and in which forms
- Maximum ADU size for your lot, usually expressed as a share of the principal dwelling or a hard square-foot cap
- Height limit for a detached unit
- Rear and side setbacks for a detached structure
- Lot coverage headroom
- Any owner-occupancy requirement
- Rental license process and inspection scope
Get these answers in a single call with your address in hand. They determine the entire project.
Costs in Saint Paul
| Type | Cost |
|---|---|
| Basement interior ADU | $95,000–$175,000 |
| Attic interior ADU | $115,000–$210,000 |
| Attached addition ADU | $185,000–$330,000 |
| Detached / garage loft ADU | $210,000–$360,000 |
What Saint Paul's housing stock does to the budget
A large share of Saint Paul homes predate 1940. That brings three recurring cost items on interior ADU projects:
Ceiling height. Many pre-war basements measure under 7 feet joist to slab. Drywalling directly to joists and rerouting ductwork usually solves it; occasionally the basement simply will not work and the attic becomes the answer.
Electrical service. A second dwelling unit on a 100 amp service often triggers an upgrade to 200 amps — $2,500 to $5,000.
Foundation type. Stone and rubble foundations in the oldest neighborhoods need evaluation and often parging or interior drainage before finishing. Budget for a look before you commit.
Requirements that apply regardless of form
- Full kitchen, full bath, separate entrance
- Egress in every sleeping room: 5.7 square feet clear, sill under 44 inches
- 7 foot habitable ceiling height
- Rated fire separation between units
- Interconnected smoke and CO alarms in both units
- Independent or properly zoned heat
- Rental license and inspection if leased
Why it is worth it
Saint Paul rents for a legal one-bedroom ADU generally cover the financing on a $120,000 to $150,000 interior build within five to eight years, and the unit adds appraised value on top. For homeowners in Highland Park, Mac-Groveland, Como, and the East Side, an interior basement ADU in a house with an existing walkout or side entrance is the highest-return remodeling project available.
Build it right the first time
Design to ADU standards from the start. Fire separation, a second heat source, and a compliant separate entrance are cheap at framing and expensive after drywall.
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Frequently asked questions
Can I build an ADU in Saint Paul?
Yes. Saint Paul allows accessory dwelling units in most residential districts in interior, attached and detached forms, subject to size, height and setback limits you should confirm with DSI for your specific lot.
How much does a Saint Paul ADU cost?
A basement interior ADU runs roughly $95,000 to $175,000. A detached unit or garage loft runs $210,000 to $360,000.
What problems come up in older Saint Paul homes?
Basement ceiling height under seven feet, 100 amp electrical service needing an upgrade, and stone or rubble foundations that need evaluation before finishing.