The trend of accessory dwelling units (ADUs) in the west could work wonders in addressing the national housing backlog if successfully adopted in the country.

This is basically the gist of House Bill (HB) No. 8813, filed by Camarines Sur 2nd district Rep Luigi Villafuerte and 5th district Rep. Migz Villafuerte.

Popular in countries like the United States (US), Australia, Canada and New Zealand, ADUs—more commonly known as “granny flats” or “backyard homes”—are small, self-contained residential units built within the same lots that have existing primary dwellings.

The Villafuertes envision ADUs as part of the solution to the national housing backlog that has already reached 6.5 million units as of 2025.

The authors of HB No. 8813 noted that the successful implementation of ADU systems in these western countries “have proven to be an effective tool in increasing housing supply quickly and efficiently without requiring large tracts of new land or massive government expenditure".

An ADU is a self-contained residential unit located in the same residential lot as a primary dwelling, with its own sleeping area, kitchen, bathroom and independent entrance. In the US alone, ADUs now make up 20 percent of all housing permits in California from 2016 to 2023.

The main goals of HB No.8813 are to allow the construction of up to two ADUs per residential lot, establish a streamlined and time-bound permit system to reduce bureaucratic delays, provide tax incentives and financing support to homeowners and builders, promote modular and prefabricated housing technologies to accelerate construction, and encourage local government unit (LGUs) to integrate ADUs into their respective local housing strategies.

“The ADU system presents an effective solution in the Philippines where the mass or low-cost housing backlog has ballooned because of how expensive lands have become in urban areas,” Rep. Luigi, a deputy majority leader, said.

“Because of this cost factor, priority developers tend to focus on building middle to high-income housing units instead of the low-cost or more affordable ones,” he noted.

“With the high cost of housing materials exacerbating other housing woes like the slow process of approval of housing permits and land titles, among others, new and innovative housing solutions must be explored to complement existing government programs,” he said.

On the other hand, Rep. Migz said that with the bill, "We hope to address the continuing severe housing shortage in the Philippines by allowing the implementation and establishment of ADUs in residential lots nationwide, and at the same time simplifying permitting procedures, and providing incentives to homeowners and builders to encourage ADU development."

This housing challenge is a result of “rapid urbanization, population growth and rising land prices in urban centers, which means that more and more Filipino families lack access to adequate, safe and affordable housing”, said the Committee on Information and Communications Technology chairman.

“Without a proper and long-term solution, the housing backlog may grow significantly up to 22 million by 2040,” Rep. Migz claimed.

By allowing homeowners to construct small secondary housing units or ADUs within their residential properties, they can enjoy multiple benefits from these ADUs.

Rep. Migz said that affordable ADUs within existing communities provide supplemental income for homeowners through rental opportunities; housing options for students, workers and young families; multi-generational housing arrangements for Filipino families; and more efficient use of existing urban land and infrastructure.

“By unlocking the potential of residential lots across the country, the proposed ADU system could generate hundreds of thousands of new housing units within a few years, significantly helping address the country’s widening housing backlog,” noted Rep. Luigi.

More importantly, he added, “This measure empowers Filipino homeowners to become active partners in solving the housing crisis while generating additional economic opportunities for families and communities.”

The other authors of the bill are Camarines Sur 1st district Rep. Tsuyoshi Anthony Horibata and Bicol Saro Party-list Rep. Terry Ridon.