FHA 203(k) ADU Financing and Rental Income Guidelines — Casita & Capital
Updated November 2026
FHA 203(k) financing can combine eligible acquisition or refinance costs with rehabilitation, but the ADU design and scope must fit current HUD rules. A Limited 203(k) and a Standard 203(k) do not permit identical work. Structural additions and major construction require careful program selection.
Establish property and work eligibility
Ask the lender to confirm how the ADU affects unit classification, zoning, appraisal and eligible improvements. Standard 203(k) projects can involve a consultant, inspections and controlled draws. Contractor qualifications and completion deadlines matter as much as the projected value.
HUD permits specified treatment of ADU rental income in qualifying circumstances, but existing and proposed ADUs can have different documentation and percentage limits. Use current HUD FHA guidance rather than assuming all projected rent is usable. The lender must calculate income under the applicable rule and any overlays.
Test affordability without full rent
If expected rent is $1,500, vacancy, maintenance and the program's qualifying adjustment can leave materially less available for the mortgage. Underwriting credit is not a rental guarantee. Verify local occupancy permission and insurance for the planned use, and keep enough funds to carry the payment during construction and lease-up.
Documents and decision checkpoints
| Review item | Evidence to request | Why it matters |
|---|---|---|
| Eligibility | Written program and property requirements | A loan officer's initial discussion is not final approval |
| Monthly cost | Itemized payment including insurance and subordinate debt | Principal and interest alone understate ownership costs |
| Closing cash | Loan Estimate, credits and source-of-funds records | A credit cannot be counted twice |
| Exit terms | Payoff, prepayment and lien-release provisions | Selling or refinancing may trigger additional costs |
Compare written offers using the same loan amount, term and lock period. Ask which conditions remain outstanding and who must clear each one before closing. If a fee or qualification rule differs from an agency guide, request the lender's written explanation; lenders may impose additional requirements. Do not send tax returns, account numbers or court records to an editorial inbox.
Plan the payment and verify the source
Use the monthly payment calculator for principal, interest, taxes and insurance, and the closing cost estimator for upfront cash. A calculator estimate is not a credit decision or a rate lock. Keep HOA dues, maintenance and any second mortgage separate if the calculator does not include them.
Review the CFPB mortgage resources and HUD housing resources alongside CFPB and VA Home Loans. Verify the current publication date and the rules effective for your transaction. Agency eligibility, lender approval and legal ownership are separate determinations. This guide is educational, not an offer to lend or individualized legal or tax advice.
Compare Current Mortgage Rates
Compare current APRs, points, fees, and estimated monthly payments from participating lenders below.
Loan Program Comparison: 2026 Benchmarks
FHA 203(k) ADU Financing and Rental Income Guidelines — Compare the 3.5% down option at 580+ FICO with 10% at 500–579, lender overlays, 1.75% upfront MIP and the applicable annual MIP tier.
Historical 2025 one-unit comparison: conforming $832,750; FHA floor $541,287. County and unit-count limits can differ.
| Loan program | Down payment / equity | 2026 one-unit baseline | Costs and page-specific comparison |
|---|---|---|---|
| FHA | 3.5% at 580+; 10% at 500–579 | $541,287 floor | 1.75% upfront MIP; 0.55% annual for >95% LTV, base loan ≤$726,200, term >15 years |
| Conventional | 3%–5% subject to eligibility | $832,750 | PMI generally below 20% down |
| VA | 0% for eligible borrowers | No VA limit with full entitlement | No monthly PMI; funding fee unless exempt |
| USDA | 0% for eligible borrowers | Income, address and repayment eligibility | Guarantee and annual fees; confirm current schedule |
| Jumbo | Lender-specific cash and reserves | Above applicable conforming limit | Lender-specific pricing and insurance |
| Home Equity / Refinance | Equity and underwriting dependent | Property and lender dependent | Compare closing costs, term and break-even |
Sources: FHFA limits; HUD FHA limits.
Editorial Methodology & Primary Sources
Verification date: Not recorded; check the primary source and lender timestamp before relying on an estimate.
Rate comparisons use participating lender feeds, not a whole-market survey or guaranteed offers. Freddie Mac PMMS is a market benchmark, not a personalized quote. Calculator models rely on published regulatory formulas and disclosed assumptions rather than fabricated first-person loan testing.
Monthly principal and interest use the amortization formula P × r / (1 − (1 + r)−n), where r is the monthly note rate and n is the number of payments; at zero interest use P / n. PITI adds monthly property taxes and homeowners insurance; PMI is separate. APR includes applicable finance charges under Regulation Z and is not the note rate used for payments. Compare lender Loan Estimates for actual APR and fees.
- Consumer Financial Protection Bureau (CFPB) — Loan Estimates, APR and borrower disclosures; Regulation Z.
- U.S. Department of Housing and Urban Development (HUD / FHA) — FHA program guidance.
- U.S. Department of Veterans Affairs (VA) — VA loan eligibility and benefits.
- Freddie Mac Primary Mortgage Market Survey (PMMS) — published rate benchmarks.
- U.S. Census state tax collections — state property tax benchmarks; confirm parcel-specific assessments and exemptions with the state revenue department and local assessor.
- CFPB — state housing finance and property tax authority.
- VA Home Loans — state housing finance and property tax authority.
The payment snapshot uses illustrative annual taxes of 1% of home price, $1,200 insurance and 0.5% PMI below 20% down, not verified local quotes. Other calculators disclose their inputs and assumptions. Published guidance and lender feeds may change independently; confirm current program rules, taxes and offers before a decision.