Everything homeowners ask about building an ADU in Saint Paul — answered with 2026 data.
Yes, ADUs are allowed in Permitted use wherever there is a one-family dwelling on the lot: RL, H1 and H2 residential districts (the former R1-R4, renamed by Ord. 23-43) and RM1-RM2 multiple-family (Table 66.221), T1-T3 traditional neighborhood (Table 66.321), BC community business (converted) (66.421) and F1 Ford (66.921). An ADU is allowed only with an associated one-family dwelling on the same zoning lot (Sec. 65.913). in Saint Paul, MN. The maximum size for a detached ADU is 800 sq ft or 75% of the floor area of the principal dwelling, whichever is greater (Sec. 65.913(d)). Floor area is measured from the interior faces of the exterior walls (Sec. 60.207); DSI asks for the main house's floor plans with the permit to check the 75%. All buildings together must also stay under the district lot-coverage cap: 40% RL, 45% H1, 50% H2 (Table 66.231). Attached ADUs can be up to 800 sq ft or 75% of the principal dwelling's floor area, whichever is greater. Saint Paul has an ADU-friendliness score of 9/10. Check our full Saint Paul ADU rules page for complete zoning details.
ADU construction in Saint Paul typically costs $125,000-$350,000. The cost per square foot averages $180-$400. Garage conversions are more affordable at $95,000-$185,000, while prefab ADUs cost $150,000-$350,000. Permit fees add Valuation-based (Sec. 33.04; schedule effective 2/25/2023): $1,499 for the first $100,000 plus $8 per additional $1,000, a plan-check fee of 65% of that, and the 0.05% state surcharge — about $3,200 on a $150,000 ADU and $5,300 on $300,000, before trade permits and any SAC. 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 the floor area of the principal dwelling, whichever is greater. Attached ADUs are limited to 800 sq ft or 75% of the principal dwelling's floor area, whichever is greater. Junior ADUs (JADUs) have a cap of No junior ADU category. An ADU inside the house (basement, attic or upper floor) is an ordinary ADU with the same 800 sq ft / 75% cap. Upper-floor units need interior stair access to their primary entrance; any exterior stair goes on the side or rear, never the front, and must match the house's finish (Sec. 65.913(e)). Maximum height is Detached ADU building: flat 25 ft cap in RL-RM2 districts (Sec. 63.501(d) as amended by Ord. 23-43, which struck the old 'or the height of the house, whichever is less'). Height is measured to the average of eaves and ridge on a pitched roof (Sec. 60.203). Attached or internal ADUs follow the house's district limit: 35 ft RL and H1, 39 ft H2 (36 ft flat roof), 40 ft RM1 (Table 66.231). Heritage sites/districts: height set through design review. You are allowed up to Two ADUs for each one-family dwelling on the zoning lot on a qualifying lot.
Rear setback: Detached ADU: may sit in the required rear yard; 1 ft minimum from an alley right-of-way, otherwise 3 ft from the rear (interior) lot line (Sec. 63.501(b)). The 3 ft interior-line setback is waived with a recorded maintenance easement if the building stays 3 ft from any building next door. Attached ADU: the house's rear setback, 10 ft in RL, H1 and H2 (Table 66.231). Side setback: Detached ADU: 3 ft from interior side lot lines, with overhangs at least one-third of that or 1 ft; on a corner lot the side-street setback equals the house's; a detached building within 6 ft of the house is treated as attached for setbacks and coverage (Sec. 63.501(a)-(b)). Attached ADU: the district side setback, 5 ft in H1/H2, 10 ft in RL (Table 66.231). Front setback: A detached ADU may not stand in a required front yard, and one that includes a garage must be at least as far from the front lot line as the house (Sec. 63.501(b)). House/attached-ADU front setback: 10 ft H1/H2, 30 ft RL, adjusted toward the neighbours' setbacks under note (d) to Table 66.231. A walkway from the street to the ADU's primary entrance is required (Sec. 65.913(e)). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
None required. Saint Paul repealed minimum off-street parking requirements citywide by Ord. 21-27 (adopted Aug. 18, 2021); Sec. 63.207 now sets only maximums. Any parking you do build must be on an approved driveway outside the front yard, with access from the alley where one exists (Sec. 63.501(c)). 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. The owner-occupancy condition was removed by the 2022 ADU amendment (Ord. 22-1) and is absent from Sec. 65.913 as re-adopted in 2023. An ADU cannot be sold separately or put on its own tax parcel (65.913(f)). Combined occupancy of the house plus its ADUs is capped by the 'household' definition: six or fewer adults plus the minors in their care (Sec. 60.209, 65.913(c)). 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 DSI does not publish an ADU review time; zoning and building plan review run through DSI Plan Review (651-266-9007). A separate sewer/water service, or a plumbing alternate request to connect through the house, adds a plumbing plan review. Plan check: 65% of the building permit fee (no plan-check fee on valuations of $1,000 or less); review time not published by DSI. Pre-approved plans availability: None. Saint Paul has no pre-approved ADU plan program; DSI publishes information sheets on ADUs and the building code and on ADU sewer/water connections.
Average ADU rental income in Saint Paul: 1-bedroom units rent for $1,270-$1,630/month, 2-bedroom units for $1,540-$1,980/month. Short-term rentals: Yes, with a licence: any stay under 30 days needs a Short-Term Rental Host licence from DSI, paid per unit and renewed yearly; a non-owner-occupied unit also needs a Fire Certificate of Occupancy, and hosts need $300,000. Expected ROI: 5-11% gross rental yield on a $200,000-$350,000 detached ADU renting at $1,400-$1,900/mo (HUD FY2027 range), before taxes, vacancy, insurance and financing; a $95,000-$185,000 garage or basement conversion renting at $1,.
The minimum lot size for an ADU in Saint Paul is None for ADUs. The district lot-area minimum (9,000 sq ft RL, 1,500 sq ft H1, 1,000 sq ft H2 per principal unit) counts only principal units; ADUs are not counted (Sec. 65.913, Table 66.231). The 2022 amendment removed the earlier lot-size minimum for detached ADUs. Lot-width minimums (60 ft RL, 30 ft H1, 25 ft H2) still apply to the lot itself. 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 $95,000-$185,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
Tell us about your project and we'll pass it to ADU builders serving Saint Paul. Free, no obligation — you choose who to work with. We don't have builders in every area yet; if nobody covers yours, we'll email you to say so.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
Just browsing? Search ADU builders near you by ZIP code.