The quick read: Finance a small Boise apartment project in two loans: a construction loan from a community bank, credit union, debt fund or FHA-insured HUD 221(d)(4) lender, sized on cost and as-completed value, and a permanent loan sized on stabilized rent that repays it. Idaho adds three budget lines the lender will test: development impact fees, sales tax your contractor pays on materials, and a prorated occupancy tax in the year the building is first occupied. Tenant units do not meet the owner-occupancy test of Idaho's homeowner's exemption, so model property tax on full value. Size the takeout first, then shop the construction loan against it.
Why is a small walk-up a realistic Boise multifamily project?
Census Bureau permit data show the Boise City metro permitted 1,218 apartment units in 62 buildings of five or more units in 2025, about 19.6 units per building, so the average new apartment building in the metro is a mid-size walk-up rather than a tower, and that size decides which lenders compete for the loan.
2025 permits, buildings with 5+ units: 62 buildings and 1,218 units in the Boise City, ID metro, per the Census Bureau's 2025 annual CBSA building permits file.
2025 permits, single-family: 7,970 one-unit buildings, per the same file.
2025 permits, 2 to 4 units: 83 two-unit buildings with 166 units and 21 three- and four-unit buildings with 84 units, per the same file.
2025 reported construction value, 5+ unit buildings: $191.6 million, per the same file.
Illustrative (our arithmetic): 1,218 units across 62 buildings is about 19.6 units per building; the 1,218 apartment units were about 12.9% of the 9,438 units permitted in the metro that year; and $191.6 million of reported value over 1,218 units is about $157,000 a unit. Permit value excludes land and is not a budget, and the figures cover the whole metro, a wider area than the City of Boise.
For the investor, the realistic project is a twelve- to twenty-four-unit walk-up on an infill or arterial parcel. With five or more units it falls outside one-to-four-unit residential programs and is financed as commercial real estate, so the property decision becomes two lender questions: who funds construction, and what loan repays it.
What does Idaho law add to the cost of a Boise apartment build?
Idaho law adds three cost lines a Boise apartment budget has to carry: development impact fees collected no earlier than construction start or building-permit issuance, sales tax the general contractor pays on its materials, and a prorated occupancy tax once the new building is first occupied, before the property reaches a full tax roll.
Impact fee limit: development impact fees shall not exceed a proportionate share of the cost of system improvements, per Idaho Code 67-8204.
Impact fee timing: a fee may be collected no earlier than the commencement of construction or the issuance of a building permit, per the same section.
Impact fee credits: a development impact fee ordinance must include a provision for credits under section 67-8209, per the same section.
What fees can fund: water, wastewater, roads, stormwater, parks and public safety facilities, per the definition of public facilities in Idaho Code 67-8203.
Contractor sales tax: the Idaho State Tax Commission says contractors are the consumers of all the goods they use and must pay sales tax on all purchases used to build, improve, repair or alter real property, per its contractor guide last updated May 26, 2026.
Occupancy tax: Idaho Code 63-317 provides for an occupancy tax on newly constructed and occupied residential, commercial and industrial structures, prorated for the portion of the year the structure was occupied.
Each line lands in a different part of the loan. Idaho lets impact fees be collected as early as permit issuance or construction start, so plan them as an early cash need, often funded from equity before the first draw. Contractor sales tax sits inside the general contractor's price, so check that the guaranteed-maximum or fixed price includes it. The occupancy tax arrives during lease-up, when rent has not yet covered costs, so carry it in the operating deficit or interest reserve. Ask the City of Boise for the current impact fee schedule for your parcel and unit sizes, and ask whether any road fees are assessed by a separate agency, before the budget goes to lenders.
Can a Boise apartment building count on short-term rental income?
Idaho law bars a city or county from enacting or enforcing an ordinance that has the express or practical effect of prohibiting any type of short-term rental, so Boise cannot ban nightly rental outright, but a construction lender still sizes the takeout on the income a permanent lender will credit.
Short-term rental limit on cities: neither a county nor a city shall enact or enforce any ordinance that has the express or practical effect of prohibiting any type of short-term rentals, per Idaho Code 67-6539. The same section still lets local governments apply general rules on noise, parking, nuisance and traffic.
The lending question is separate from the zoning one. A permanent lender sizes on the income it is willing to credit, and it may discount nightly income or exclude it. Build the pro forma on long-term rent, show any nightly units on a separate line, and ask each lender in writing how it treats them. Confirm the parcel's zone with the City before pricing either plan, because a construction lender sizes against an approved building, not a hoped-for one.
Who lends on a small apartment construction loan in Boise?
Four lender types finance a Boise apartment walk-up under construction: community and regional banks, credit unions, private debt funds and lenders using FHA-insured HUD 221(d)(4), a MAP-eligible program. Only the federal bank guidelines and HUD's program page publish terms that apply across a lender type, so most comparisons are questions you put to lenders in writing.
Boise small-apartment construction lenders by type (bank row from 12 CFR Part 365, Appendix A; HUD row from HUD's multifamily programs page; index rates from FRED, prime as of 2026-10-02 and SOFR as of 2026-10-08; every other cell has no public, dated source, so it is the question to ask):
| Lender type | Leverage test | Recourse and equity | Rate basis | What repays it |
|---|---|---|---|---|
| Lender type Community or regional bank | Leverage test Supervisory limit of 80% of value for multifamily construction, with capped exception lending; disbursements should not exceed actual construction outlays | Recourse and equity Guidelines tell banks to set limits on nonrecourse loans, guarantor support and minimum hard equity | Rate basis Ask whether it floats over prime (7.00% on 2026-10-02) or SOFR (3.87% on 2026-10-08), plus the spread and floor | What repays it Guidelines tell banks to set requirements for takeout commitments; ask whether yours needs one at closing |
| Lender type Credit union | Leverage test No public, dated source; ask for maximum loan-to-cost and loan-to-value | Recourse and equity Ask whether personal and completion guaranties are required | Rate basis Ask for the index, spread and floor | What repays it Ask whether it will hold a mini-perm after completion |
| Lender type Private debt fund | Leverage test No public, dated source; ask for loan-to-cost and the as-completed value test | Recourse and equity Ask for completion, carry and carve-out guaranty terms | Rate basis Ask for the index, spread, floor and any rate cap | What repays it A refinance or sale; ask for the extension tests and fees |
| Lender type HUD 221(d)(4), FHA-insured | Leverage test HUD's page covers rental housing with 5 or more units; ask a MAP lender for the sizing tests | Recourse and equity Ask the MAP lender; the cited HUD page states no recourse term | Rate basis Ask the lender; the cited HUD page publishes no rate | What repays it A long-term insured mortgage of up to 40 years, per HUD |
Bank supervisory limit, multifamily construction: 80% of value, per 12 CFR Part 365, Appendix A.
Bank supervisory limit, land development: 75% of value, per the same appendix.
Exception loans: the aggregate of loans above the limits should not exceed 100 percent of total capital, and those on commercial, agricultural, multifamily or other non-1-to-4 family property should not exceed 30 percent of total capital, per the same appendix.
Prime rate: 7.00% on 2026-10-02, per the FRED series DPRIME.
SOFR: 3.87% on 2026-10-08, per the FRED series SOFR.
The 80% figure is a supervisory guideline for a bank's internal policy, not a promise of 80% leverage, and a bank can lend above it as an exception within its capped exception volume. In practice the binding number is usually the bank's own loan-to-cost and its view of the refinance. Money is released in draws against the budget, so read the draw, inspection and retainage terms as closely as the rate.
What repays the construction loan on a Boise apartment building?
A permanent loan sized on stabilized rent repays the construction loan, so the first question on a Boise walk-up is what the finished building will earn after property tax at full value, because that refinance amount sets how much construction debt the plan can carry and how much equity stays in the deal.
Three takeout routes exist for a new small building, and they run on different clocks:
- Bank or credit union mini-perm: the construction lender converts or extends the loan after completion. Ask for the conversion test in writing at the construction closing, and compare it with a separate permanent loan using our guide to mini-perm versus construction-to-permanent loans.
- HUD 221(d)(4): HUD describes it as insuring the construction or rehabilitation of rental or cooperative housing with 5 or more units, with long-term mortgages of up to 40 years, and the program is eligible for Multifamily Accelerated Processing.
- HUD 223(f) later: HUD says the property must have been completed or substantially rehabilitated for at least 3 years before the application, with a term of up to 35 years or 75 percent of the estimated life of the improvements, whichever is less. A building finished this year is not a day-one 223(f) refinance.
Idaho homeowner's exemption: the lesser of $125,000 or 50% of market value of a homestead is exempt, and the homestead must be owner-occupied and used as the owner's primary dwelling place, per Idaho Code 63-602G.
That owner-occupancy test is the Idaho tax point for an investor. A tenant-occupied unit is not the owner's primary dwelling, so model the rental units' property tax on full market value, and model the occupancy-tax year during lease-up as its own cost. A permanent lender sizes on net operating income after that tax line.
How does an illustrative 16-unit Boise walk-up size up?
An illustrative 16-unit Boise walk-up shows why the takeout should be sized first: at an assumed 60% loan-to-cost the modelled permanent loan falls about $61,973 short of the construction payoff, while at an assumed 55% loan-to-cost the same refinance clears the payoff by about $138,027.
Every input below is an assumption, not a quote, a market rent or an Ada County tax rate.
Illustrative (our arithmetic) total project cost: $4,000,000 for sixteen units, including land, hard costs with contractor sales tax, impact fees, soft costs and interest reserve.
Illustrative (our arithmetic) rent: sixteen units at an assumed $1,850 a month is $355,200 a year; less an assumed 5% vacancy, $337,440.
Illustrative (our arithmetic) operating costs before property tax: an assumed $80,000 a year.
Illustrative (our arithmetic) property tax on full value: an assumed $4,500,000 as-completed value at an assumed 0.85% combined rate is $38,250 a year.
Illustrative (our arithmetic) net operating income: $337,440 less $80,000 less $38,250 is $219,190.
Illustrative (our arithmetic) refinance: at an assumed 1.25x coverage, $219,190 supports $175,352 of annual debt service; at an assumed 7.5% loan constant that is about $2,338,027 of loan.
Illustrative (our arithmetic) construction loan at 60% of cost: $2,400,000, about $61,973 more than the refinance supports.
Illustrative (our arithmetic) construction loan at 55% of cost: $2,200,000, about $138,027 less than the refinance supports, with $1,800,000 of equity instead of $1,600,000.
The value test does not bind here: illustrative (our arithmetic), 80% of the assumed $4,500,000 value is $3,600,000. The refinance does. Run the same check with your own budget before you ask for terms, because a slower lease-up or a higher rate at conversion moves the shortfall the wrong way.
How do you get lenders competing for a Boise apartment construction loan?
You get lenders competing for a Boise apartment construction loan by sending one complete package, with budget, plans, schedule, Idaho cost lines and the takeout plan, to several lender types at once, then comparing their written terms side by side instead of negotiating one quote at a time.
YieldStack is an AI-native commercial mortgage brokerage that arranges financing for commercial real estate investors. Software finds and compares financing options across 20,000+ loan programs; human brokers structure the deal, negotiate for the borrower and carry it toward closing. Every credit decision is made by the lender; YieldStack arranges the introductions and negotiates on the borrower's side, and no loan, rate, or closing is guaranteed.
Have this ready before you ask for terms:
- Development budget: land, hard costs with contractor sales tax, impact fees, soft costs, contingency and interest reserve, line by line.
- Plans and schedule: drawings, zoning and permit status, and a month-by-month construction and lease-up schedule showing the occupancy-tax year.
- General contractor: contract type, track record and bonding capacity.
- Pro forma: stabilized long-term rents, property tax on full value, and any nightly income shown on a separate line.
- Takeout plan: the permanent loan you expect, its sizing test and the payoff it has to cover.
- Sponsor package: schedule of real estate owned, personal financial statement and completed-project history.
It costs Zero upfront to submit a deal and review offers; YieldStack's broker fee is 0.50–1.00% of the loan amount and is paid only at closing.
Send your Boise apartment construction deal for side-by-side lender terms
For local context, see the Boise market page and the statewide Idaho market page.
The bottom line
A small Boise apartment project is financed in two steps: a construction loan from a bank, credit union, debt fund or FHA-insured lender, and a permanent loan that repays it from stabilized rent. Budget impact fees, contractor sales tax and the occupancy-tax year, model property tax on full value, size the takeout first, and get every lender's terms in writing before you close.