US Federal 2025-2026 Regular Session

US Federal House Bill HB4479

Introduced
 
Introduced
7/17/25  

Caption

To amend the National Housing Act to direct the Secretary of Housing and Urban Development to establish a program to insure certain second liens secured against property for the purpose of financing the construction of an accessory dwelling unit, and for other purposes.

Summary

HB4479 would require the Secretary of Housing and Urban Development to create, within two years of enactment, an insurance program for certain second liens used to finance the construction of accessory dwelling units (ADUs). The bill sets limits on the size of the insured second lien, generally capping it at the lesser of 30 percent of the FHA loan limit for a one-unit home or the amount that, together with other liens, does not exceed the projected post-construction value of the property. It also allows the insured amount to be increased based on a portion of expected rental income from the ADU. The bill defines an accessory dwelling unit broadly to include modular or prefabricated units, manufactured housing, or conversions of existing structures, so long as the unit includes kitchen, sleeping, and bathroom facilities and is added to, created within, or detached from a single-family property. Borrowers would need to apply and certify ownership, and HUD could charge an annual premium of up to 1 percent of the insured principal. HUD would also have to report annually to Congress and may issue implementing regulations.

Impact

HB4479 would amend Title II of the National Housing Act by adding a new Section 259, creating a federal insurance mechanism for second-lien financing tied to ADU construction. It would also direct the Federal Housing Finance Agency to allow Fannie Mae and Freddie Mac to purchase and securitize loans insured under the new program, unless the FHFA Director determines that market conditions create excessive and unmitigable risk and formally prohibits such activity. The bill would therefore expand federal housing finance support for ADU development and potentially make it easier for homeowners to access financing for adding rental or family housing on existing single-family lots.

Sentiment

Based on the bill text and the absence of recorded committee debate or votes, the measure appears to be framed positively as a housing-supply and affordability tool. Its sponsors span a range of House Democrats, suggesting support among members interested in expanding middle-income housing options and encouraging infill development. No formal vote history or hearing transcript is provided, so there is no documented opposition or bipartisan negotiation reflected in the available record.

Contention

The main policy questions likely concern federal exposure to risk, the use of insured second liens, and the effect on mortgage markets. Supporters would likely emphasize that the bill could help homeowners finance ADUs and increase housing supply, while critics may worry about default risk, property valuation assumptions, and whether federal backing could encourage overleveraging. The FHFA exception for market stress suggests a built-in concern that securitization of these loans could pose risks under adverse conditions, but no specific objections are recorded in the provided materials.

Companion Bills

US HB4568

Same As Supporting Upgraded Property Projects and Lending for Yards (SUPPLY) Act

Previously Filed As

US HB3988

To direct the Secretary of Housing and Urban Development and the Director of the Bureau of the Census to conduct a study and submit a report about how Federal agencies identify and record cases of housing loss in the United States, and for other purposes.

US SB3178

A bill to require the Secretary of Housing and Urban Development and the Secretary of Agriculture to withdraw a final determination relating to energy efficiency standards for housing, and for other purposes.

US HB5340

To prohibit the disclosure of records by the Secretary of Housing and Urban Development of individuals for the purposes of immigration enforcement, and for other purposes.

US HB5909

To direct the Secretary of Housing and Urban Development to establish procedures for reporting of condemned Federally assisted rental housing and to authorize penalties related to such condemned housing, and for other purposes.

US HB5263

To require approval from the Secretary of Housing and Urban Development for any Federal manufactured home and safety standards, and for other purposes.

US LD2173

An Act to Update the Laws Regarding Housing Developments and Accessory Dwelling Units

US HB2494

To direct the Secretary of Housing and Urban Development to annually submit to the Congress a report that analyzes State and local strategies, activities, and plans that promote affordable housing, and for other purposes.

US HB5907

To authorize the Secretary of Housing and Urban Development to award grants to eligible entities to select pre-reviewed designs of covered structures of mixed-income housing for use in the jurisdiction of the eligible entity, and for other purposes.

US HB464

A BILL to amend and reenact ยง 36-139 of the Code of Virginia, relating to Department of Housing and Community Development; powers and duties of Director; accessory dwelling unit construction guide.

US HB8075

To authorize the Secretary of the Treasury to direct the Federal Deposit Insurance Corporation and the National Credit Union Administration to establish emergency transaction account guarantee programs, and for other purposes.

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