Eagan, MN Accessory Structures: ADU Rules (2026)

Subdivision 32.C limits every property in a single-family district to one dwelling unit unless it qualifies as an ADU under a long checklist. The primary residence has to sit in an Estate or R-1 district to begin with. Size is capped two ways: no more than 960 square feet or 33 percent of the primary residence's footprint, whichever is less, though an ADU also cannot be smaller than 300 square feet. Design has to match the main house's architectural style, color and character, and the ADU cannot rise higher than the primary residence.

Location is restricted to inside or attached to the primary residence; the code specifically bars ADUs in detached accessory buildings, detached garages or workshops. An ADU can be created by converting existing living space, but converting garage space only works if a new two-car or larger garage goes up elsewhere on the lot without needing a variance. Occupancy is capped at two residents and two bedrooms per ADU, and only one ADU is allowed per lot at all. Two additional off-street parking spaces are required for the ADU on top of what the primary residence already needs.

If the ADU has its own exterior door, that door cannot sit on the same building facade as the primary residence's front entrance. Building coverage on the whole lot, including the ADU, cannot exceed 20 percent, and the primary residence and ADU can only be served by a single water and sewer service line from the street.