How much rental income does a Boise ADU generate?
Long-term monthly rent ranges in 2026 Boise: Goldfinch (280 sq ft studio) $1,100-$1,250, Waxwing (396 sq ft studio) $1,300-$1,500, Kingfisher (491 sq ft 1BR) $1,500-$1,800, Kestrel (695 sq ft 2BR) $1,900-$2,400. Sandpiper and Osprey (studio + garage) match the Waxwing on dwelling rent plus optional $100-$200/mo for the garage. These are gross monthly rents; net income is typically 70-80% of gross after tax, insurance, vacancy, and reserves.
Rent ranges by plan
| Plan | Sq Ft | Type | Boise long-term rent | Garage rent (if applicable) |
|---|---|---|---|---|
| Goldfinch | 280 | Studio | $1,100-$1,250/mo | — |
| Waxwing | 396 | Studio | $1,300-$1,500/mo | — |
| Sandpiper | 396 | Studio + garage | $1,300-$1,500/mo | $100-$200/mo |
| Osprey | 376 | Studio + garage | $1,250-$1,450/mo | $100-$200/mo |
| Kingfisher | 491 | 1 BR | $1,500-$1,800/mo | — |
| Kestrel | 695 | 2 BR | $1,900-$2,400/mo | — |
These are baseline ranges across most Boise residential neighborhoods. Premium neighborhoods (North End, Hyde Park, near the Greenbelt) command the high end. Outer areas (Boise Bench, southwest Boise) sit at the low end. Eagle commands a 5-10% premium on equivalent units; Caldwell and Nampa typically run at parity or slightly below the Boise baseline.
Gross yield by plan
| Plan | Build cost (Standard) | Annual gross rent | Gross yield |
|---|---|---|---|
| Goldfinch (280 sf) | $130k | $14,400 | ~11.1% |
| Waxwing (396 sf) | $160k | $16,800 | ~10.5% |
| Kingfisher (491 sf) | $200k | $19,800 | ~9.9% |
| Kestrel (695 sf) | $285k | $25,800 | ~9.1% |
Gross yield trends down slightly with size — bigger plans deliver more absolute rent but cost proportionally more to build. For pure cap-rate plays, smaller plans win. For absolute monthly income and the broader tenant pool, larger plans win. See our ADU ROI guide for the net-yield breakdown.
Net yield after operating costs
Net yield typically runs 1.5-3 percentage points below gross — a Kingfisher's 9.9% gross becomes 7-8% net after property tax, insurance, vacancy reserve (5-8% of gross rent), maintenance reserve (5-8%), and any property management (typically 8-10% of gross). The biggest variable is whether the homeowner manages the ADU themselves or hires a property manager.
Short-term rental income (STR)
Permitted STRs in high-demand Boise neighborhoods (North End, Hyde Park, near the Greenbelt) clear $120-$180/night for a 1-bedroom Kingfisher. At 65% occupancy, that's $2,300-$3,500/mo gross — substantially more than long-term. But STR comes with cleaning costs ($75-$150/turnover), platform fees (Airbnb/Vrbo 12-15%), transient room tax, an STR permit from the city, and meaningfully more operational overhead. Net income often lands within $300-$500/mo of long-term once you account for everything. Full breakdown: Can you Airbnb an ADU in Boise?.
Tenant pool by plan
- Goldfinch: single graduate students, traveling nurses at St. Luke's or Saint Al's, single professionals
- Waxwing: single professionals, occasional couples, full-time home-office tenants
- Kingfisher: couples, single professionals wanting a real bedroom, in-law suites
- Kestrel: families with one child, two roommates sharing, couples with home office, multigenerational households
- Sandpiper / Osprey: any of the studio tenants above plus garage tenants (typically separate)
How rents vary across Treasure Valley cities
Boise sets the baseline. Eagle typically commands 5-10% premium reflecting higher household incomes. Meridian runs at parity. Garden City is at the Boise baseline. Caldwell and Nampa typically run 5-15% below baseline. Kuna and Star sit between Nampa and Meridian. Verify against current Apartment List, Zillow, and Rentometer data before locking expectations.
Where to next
Ready to build out the rental math for your specific situation? The Boise ADU Rental Income money page collects the per-plan rent ranges, yield math, and a rent-by-neighborhood snapshot in one place. The ROI Calculator layers financing on top — gross yield, monthly cash flow after debt service, payback, and 10-year cash-on-cash. Build-side reads: Boise's six pre-approved plans (each plan's cost and rent ceiling on one page), the backyard cottage builder page (detached rental optimization), and the design-build contractor overview. Get a parcel-specific recommendation via the free lot check.
Sources & References
- Apartment List — Boise rent report
- Zillow Rental Market Report
- AirDNA — STR market data — Used to model STR occupancy and ADR ranges
- City of Boise — Short-term rental permit program