Affordable Housing Funding Sources: LIHTC, HUD, and Compliance Rules

Affordable rental housing is almost always built by stacking capital from several places at once, because no single program covers the full gap between what lower-income tenants can pay and what a building costs to build and run. The main affordable housing funding sources are federal Low-Income Housing Tax Credits, HUD grants like HOME and CDBG, project-based rental subsidies, the National Housing Trust Fund, state and local housing trust funds, and private capital from CDFIs, banks meeting Community Reinvestment Act obligations, Opportunity Zone investors, and mission-driven philanthropy. Each source carries its own income limits, affordability period, and compliance rules, and those rules shape the deal as much as the dollars do.

Low-Income Housing Tax Credits

The Low-Income Housing Tax Credit, authorized by Section 42 of the Internal Revenue Code, produces more affordable rental housing than any other federal program. State housing agencies get an annual allocation based on population and award credits to developers through a competitive application process. The developer sells the credits to investors, usually large banks or insurers, who claim them against federal tax over ten years. That equity reduces how much the project has to borrow, and lower debt service is what makes below-market rents possible.¹

The 9% and 4% Credits

There are two tiers. The 9% credit is highly competitive and produces equity worth roughly 70% of a project’s qualified basis for new construction that is not otherwise federally subsidized. State agencies rank applicants and fund only the strongest each year, so demand runs well past supply.

The 4% credit is not capped in the same way. It covers about 30% of qualified basis and is available to any project financed at least 50% with tax-exempt private activity bonds.¹ Because the credit amount is smaller, 4% deals almost always need additional gap financing from other public sources.

Income Tests and the Basis Boost

Every tax credit property has to satisfy one of three income-targeting elections. The 20-50 test requires at least 20% of units to serve households at or below 50% of area median gross income. The 40-60 test requires at least 40% of units at or below 60% of AMI. The average income test lets a developer set individual units anywhere from 20% to 80% of AMI, as long as the project-wide average stays at or below 60%.¹

Projects sited in a Qualified Census Tract or Difficult Development Area can claim a basis boost that raises eligible costs by up to 30%, producing more credits and more investor equity. HUD updates the designated tracts and areas annually.²

Compliance Period and Recapture

Tax credit properties must operate under affordability restrictions for at least 30 years: a 15-year initial compliance period plus an extended use period of at least 15 more years. If qualified basis drops during the compliance period because units fall out of compliance, the IRS recaptures a share of the credits already claimed, with interest at the federal overpayment rate.³ Recapture hits investor returns hard, which is why investors watch compliance closely for the full 15 years.

HUD Grant and Voucher Programs

HOME Investment Partnerships

HOME is the largest federal block grant dedicated exclusively to affordable housing. HUD sends the money by formula to state and local participating jurisdictions, which use it for land acquisition, rehabilitation, or new construction of rental and homeownership units. Jurisdictions have to put up matching local funds equal to at least 25% of what they draw down each year.⁴

HOME-funded rentals carry affordability periods tied to the per-unit investment: 5 years for rehabilitation under $25,000, 10 years for $25,000 to $50,000, 15 years for over $50,000 or projects involving refinancing, and 20 years for new construction. The restrictions have to be recorded as deed restrictions or covenants running with the land.⁵

Community Development Block Grants

CDBG provides annual formula grants to cities, counties, and states for community development benefiting low- and moderate-income residents.⁶ The program’s mission is broader than HOME, but CDBG dollars often support housing work indirectly: acquiring land for future affordable sites, removing lead paint, or paying for infrastructure that makes a development feasible.

Project-Based Vouchers

HOME and CDBG help pay for construction. Project-Based Vouchers help pay the rent once the building opens. A public housing authority attaches voucher assistance to specific units under a Housing Assistance Payments contract with the owner, and the voucher covers the gap between the tenant’s payment and the unit’s gross rent.⁷ Because the subsidy stays with the building rather than following the tenant, lenders and investors will underwrite the voucher income, making PBVs a real financing tool for deals serving extremely low-income households.

Choice Neighborhoods

Choice Neighborhoods provides planning grants and larger implementation grants for transforming severely distressed public housing and the surrounding area, typically by replacing units with mixed-income developments.⁸ The awards are competitive and few in number, but they can pull in significant local and private co-investment.

The National Housing Trust Fund

The Housing Trust Fund is aimed at the hardest-to-serve renters. In any year total HTF funding falls below $1 billion, grantees must spend 100% of their allocation on extremely low-income households, meaning those at or below 30% of area median income. Above $1 billion, at least 75% still has to serve that group.⁹ Because allocations have stayed below the threshold, HTF has effectively functioned as an ELI-only tool.

Eligible uses include acquisition, new construction, rehabilitation, demolition, and operating cost assistance for up to 30% of a grant.¹⁰ The operating cost piece is unusual among federal housing programs and helps make deep-affordability projects viable when rents alone cannot cover building expenses.

State and Local Housing Trust Funds

Most states and many cities run their own housing trust funds, typically capitalized through dedicated revenues like real estate transfer taxes, document recording fees, or voter-approved bonds. The money is locally generated, so it can be deployed with fewer strings than federal programs: below-market loans, deferred-payment second mortgages, or grants with terms tailored to each deal.

Local trust funds most often show up as the last layer of gap financing after tax credits, HOME dollars, and private debt are already in place. Some jurisdictions use them for things federal programs restrict, like predevelopment costs or units serving households slightly above federal income ceilings. Loan repayments from earlier projects often flow back into the fund, creating a revolving pool that is less vulnerable to shifting federal appropriations.

Private and Philanthropic Capital

Community Development Financial Institutions

CDFIs are mission-driven lenders certified by the U.S. Treasury’s CDFI Fund. They finance projects that conventional banks would pass on because the returns are thin or the borrower lacks a standard credit profile. Treasury invests federal dollars alongside private capital in these lenders, and its Capital Magnet Fund specifically targets affordable housing in low-income communities.¹¹ Many CDFIs also help smaller nonprofit developers structure deals and apply for larger public subsidies.

Community Reinvestment Act Lending

The Community Reinvestment Act requires regulated banks to help meet the credit needs of the communities where they operate, including low- and moderate-income neighborhoods.¹² In practice, banks invest as equity in tax credit projects, make construction and permanent loans to affordable developers, and buy bonds that finance affordable deals. Regulators grade CRA performance during bank exams, and a weak rating can block expansion or a merger, which channels billions of dollars into affordable housing every year.

Opportunity Zone Investments

The Opportunity Zone program, created by the Tax Cuts and Jobs Act of 2017, lets investors defer and potentially reduce tax on capital gains that are reinvested through a Qualified Opportunity Fund into designated high-poverty census tracts. An investor who holds the fund interest for at least 10 years can elect to exclude all appreciation on the new investment from taxable income.¹³

One boundary to keep in mind: all deferred capital gains must be recognized no later than December 31, 2026, regardless of whether the investor sells the fund interest, so the deferral benefit effectively ends in 2026. The program itself does not require that investments serve low-income residents, though some state housing finance agencies have worked to steer Opportunity Zone capital into affordable deals by layering it with tax credits and other subsidies.

Philanthropic and Impact Capital

Foundations, impact investors, and mission-driven funds provide what developers call patient capital: loans or equity that accept lower returns and longer timelines than conventional financing. It matters most during predevelopment, when a developer is paying for environmental studies, architects, and market analysis before construction financing exists. A philanthropic predevelopment loan can keep a project alive long enough to secure tax credits and grants, and it is typically repaid or rolled into permanent financing once the larger commitments land.

Compliance Rules That Travel With the Money

Every public dollar comes with strings, and the following obligations apply across most federal housing programs. Missing any of them can cost a developer its funding, its tax credits, or its eligibility for future awards.

Prevailing Wage

Federal law requires workers on HUD-funded construction to be paid at least the locally prevailing wage set by the Department of Labor. Unit thresholds vary: HOME-funded projects trigger the requirement at 12 or more units, CDBG-funded rehabilitation at 8 or more, and public housing construction is covered regardless of size.¹⁴ Prevailing wage rules raise construction costs, so experienced developers price them into the budget from the start.

Environmental Review

All HUD-assisted projects have to complete an environmental review under the National Environmental Policy Act before any funds from any source are committed. For most programs, the local jurisdiction is the responsible entity and conducts the review under 24 CFR Part 58, evaluating potential impacts including contamination, floodplains, historic preservation, noise, and endangered species.¹⁵ The timing trap catches developers off guard: spending money on the site before the review is complete, even non-federal money, can disqualify the entire project from HUD funds.

Section 3 Hiring

Section 3 of the Housing and Urban Development Act of 1968 requires HUD-funded projects to direct employment, training, and contracting opportunities to low- and very low-income residents to the greatest extent feasible. HUD publishes numerical benchmarks, and beginning in January 2026 public housing authorities must submit annual compliance reports through HUD’s Section 3 Reporting System.¹⁶

Affirmative Fair Housing Marketing

Federally funded developments must adopt an Affirmative Fair Housing Marketing Plan identifying demographic groups least likely to apply without targeted outreach, along with the specific advertising methods, community contacts, and staff training the property will use.¹⁷

Single Audit and Financial Reporting

Any organization spending $1,000,000 or more in federal awards during a fiscal year must undergo a Single Audit under 2 CFR 200.501, covering both financial statements and program compliance.¹⁸ Most funding programs also require annual operating budgets, audited property financials, and physical inspections to confirm units are safe and occupied by income-eligible tenants.

What Noncompliance Costs

For tax credit properties, a drop in qualified basis during the 15-year compliance period triggers recapture of a portion of credits already claimed, with interest.³ For grant-funded projects, HUD can demand immediate repayment or impose a limited denial of participation that shuts a developer out of HUD programs in a defined geographic area, on grounds including failure to perform a contract or comply with program requirements.¹⁹ A debarment ends a developer’s ability to do affordable housing work, so most treat compliance as core to the business rather than a back-office task.

1
Office of the Law Revision Counsel. 26 USC 42 – Low-Income Housing Credit
2
HUD USER. 2025 and 2026 Small DDAs and QCTs
3
Internal Revenue Service. IRC 42, Low-Income Housing Credit – Part VII Computing the Credit Recapture Amount
4
eCFR. 24 CFR Part 92 – Home Investment Partnerships Program
5
eCFR. 24 CFR 92.252 – Qualification as Affordable Housing – Rental Housing
6
U.S. Department of Housing and Urban Development. Community Development Block Grant Program
7
eCFR. 24 CFR Part 983 – Project-Based Voucher (PBV) Program
8
U.S. Department of Housing and Urban Development. Choice Neighborhoods
9
HUD USER. Housing Trust Fund (HTF) Income Limits
10
U.S. Department of Housing and Urban Development. National Housing Trust Fund Factsheet
11
CDFI Fund. Community Development Financial Institutions Fund
12
Office of the Law Revision Counsel. 12 USC 2901 – Congressional Findings and Statement of Purpose
13
Office of the Law Revision Counsel. 26 USC 1400Z-2 – Special Rules for Capital Gains Invested in Opportunity Zones
14
U.S. Department of Housing and Urban Development. HUD Davis Bacon Related Acts
15
HUD Exchange. Orientation to Environmental Reviews
16
HUD Exchange. Section 3
17
U.S. Department of Housing and Urban Development. Affirmative Fair Housing Marketing Plan
18
eCFR. 2 CFR 200.501 – Audit Requirements
19
eCFR. 2 CFR Part 2424 – Nonprocurement Debarment and Suspension