Everything homeowners ask about building an ADU in Saint Paul — answered with 2026 data.
Yes, ADUs are allowed in All residential zones with one-family dwellings (citywide since 2018) in Saint Paul, MN. The maximum size for a detached ADU is 800 sq ft or 75% of principal dwelling floor area (whichever greater). Attached ADUs can be up to 800 sq ft or 75% of principal dwelling floor area (whichever greater). Saint Paul has an ADU-friendliness score of 7/10. Check our full Saint Paul ADU rules page for complete zoning details.
ADU construction in Saint Paul typically costs $135,000-$270,000. The cost per square foot averages $130-$270. Garage conversions are more affordable at $65,000-$155,000, while prefab ADUs cost $95,000-$220,000. Permit fees add $1,900-$3,200 to your budget. See our detailed Saint Paul ADU cost guide.
Detached ADUs in Saint Paul can be up to 800 sq ft or 75% of principal dwelling floor area (whichever greater). Attached ADUs are limited to 800 sq ft or 75% of principal dwelling floor area (whichever greater). Junior ADUs (JADUs) have a cap of 800 sq ft or 75% of principal dwelling (internal ADU). Maximum height is 25 ft or height of principal structure (whichever less) for detached; district standard for attached. You are allowed up to 2 ADUs per one-family dwelling (at least 1 must be detached if both built) on a qualifying lot.
Rear setback: 3 ft from interior lot lines. Side setback: 3 ft from interior lot lines. Front setback: Must meet principal building front setback (ADUs placed in rear). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
No additional parking required. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required (removed in 2022). Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Saint Paul is typically 45-65 days. The plan check process takes approximately 2-3 weeks. Pre-approved plans availability: Available.
Average ADU rental income in Saint Paul: 1-bedroom units rent for $1,300-$1,750/mo/month, 2-bedroom units for $1,650-$2,300/mo/month. Short-term rentals: Permitted with license. Expected ROI: 7-9% annual return.
The minimum lot size for an ADU in Saint Paul is No minimum (lot size requirement removed in 2022). This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Saint Paul, a garage conversion typically costs $65,000-$155,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.