On Wednesday, October 13, the New York State Assembly held a hearing on a proposed bill to legalize “accessory dwelling units,” or ADUs, across the state. This commentary is adapted from testimony provided at that hearing by the author.   

All New Yorkers deserve a safe, affordable place to live in the city, town, or neighborhood that they wish. Unfortunately, too many are denied that security and opportunity: our housing crisis has forced disproportionately low-income, Black and brown, and immigrant New Yorkers into homes where they live in fear of a safety inspection, or are denied the ability to live in communities with good jobs and schools to begin with.

While addressing New York’s homelessness, housing affordability, and residential segregation crises will require a multi-pronged, comprehensive policy approach, legalizing basement apartments, garage conversions, “in-law suites,” and other types of “accessory dwelling units,” or “ADUs,” would be a significant step in the right direction. ADUs, which refers broadly to any secondary unit on the same lot as a primary residence, have been an important housing solution for decades.

The Benefits of Basement Apartments, “In-law Suites,” and Other Secondary Units

Basement apartments, “in-law suites,” and other types of secondary units provide both additional income and space for homeowners and affordable housing for tenants. Though reliable data on households with or living in secondary units is hard to come by, in part because of their prohibition in many places, a study of Babylon, Long Island shows how legalizing these types of homes can be a win for all parties. Rent for garage conversions, basement apartments, and other accessory homes was 35 percent more affordable, on average, than non-accessory homes, providing New Yorkers much-needed access to affordable housing. At the same time, the rental income from these units helps middle-class families: homeowners with accessory units had incomes that were on average 23 percent lower than for those without.

Taking a more systemic view, allowing more secondary units can provide critical housing growth without significantly changing the built environment of a neighborhood, increase property values and thus local revenues, and provide socioeconomic integration in places where restrictive zoning has historically excluded lower-income residents.

Furthermore, they can be rented out or used as living space for a family member or care provider, a particularly relevant need as New Yorkers age. A survey of AARP members, for example, found that 77 percent want to live in their community for as long as possible, and 70 percent said they would consider building a secondary unit for a loved one who needs care.

The State of ADUs in New York

Given all of these benefits, it is no surprise that hundreds of thousands of New Yorkers are already taking advantage of accessory homes, either as owners or tenants. Because of inconsistent oversight of the number of unregistered ADUs that already exist, and complicated factors about where they could be created, estimates vary widely. New York City estimates that there are at least 50,000 basement apartments housing over 100,000 people in the city; on the other hand, the Basement Apartments Safe for Everyone (BASE) campaign estimates that there are 209,700 properties in New York City that could be conversions under the existing regulatory model. On Long Island, there are already 90,000–100,000 existing, unregulated accessory homes, according to a report from Long Island Index. The Regional Plan Association estimates that with policy changes to legalize ADUs, another 307,000 units could be created or brought into regulated status across New York City, Long Island, and the Hudson Valley. Along the same lines, the BASE Campaign has identified more than 400,000 properties in New York City alone that could become apartments under an improved regulatory model from the city and state. 

However, the onerous regulations in place for bringing existing ADUs into the regulated housing market have left hundreds of thousands of New Yorkers—disproportionately low-income and immigrants—with few safety and legal protections. We received a tragic reminder of these lack of protections at the end of August when eleven of our neighbors in Queens died in their homes due to flooding from Hurricane Ida, many in unregulated basement apartments. There is no silver bullet for these disasters, but legalization is the only path for public officials to effectively serve individuals living in unregulated units, and for those tenants to be able to assert their right to a safe home without fear of eviction.


Restrictions on the development of basement apartments, garage conversions, “in-law suites,” and other accessory homes have left a patchwork of regulations, driven up the cost of building or converting one, if allowed at all, and forced tenants into living situations that are often unsafe. Only state-level action can raise the shared policy “floor” to ensure all localities, tenants, and homeowners can reap the benefits of ADUs.

The status quo of locality-by-locality regulations has left a patchwork of oversight that leaves homeowners who want to observe important safety regulations flummoxed, and who then often resort to illegal, unregulated accessory rentals that have no safety protections at all. As homeowners Ruhel and Rupy Khan wrote in an op-ed for the New York Daily News, “Why should a New York City homeowner be able to earn spare income by renting their basement out, as we do, while someone just a short drive away is banned from building an in-law unit in their backyard for a relative or health aide?” In Glen Cove, along the North Shore of Nassau County, for example, accessory homes are banned entirely, while in nearby Oyster Bay Cove, just east, accessory homes built before 1988 are legal and can house anyone, while newer accessory homes can only be lived in by domestic employees or caretakers. This lack of consistent oversight, aside from creating confusion and leading even those with the means to build fully legal accessory units to keep them unregulated, has also contributed to regional segregation and inequality, providing safe and affordable housing and boosting the local economy in some towns, while others see younger generations leaving for lack of affordable housing.

Why the State Must Act

Perhaps even more importantly, this bill would provide critical financial support, technical assistance, and regulatory relief for all localities, regardless of the current status of ADUs in their jurisdiction. Evidence from across the country, especially in California, has shown that while legalizing ADUs is an important step for local communities, financing programs are critical for achieving success at scale. That’s why the financing program that A. 4854 directs state officials to create is so critical: you should not need to have hundreds of thousands of dollars already saved to convert an unused part of your property into a new home and create much-needed affordable housing. Government loans that give homeowners the resources they need to build or improve secondary units are strong public investments. Of course, units financed by the state should meet certain criteria, and the legislature should create a regulatory regime for these units that includes safety measures, affordability, and tenant protections.

Technical assistance is critical as well. While larger municipalities like New York City may have planning and zoning departments that can implement ADU laws independently, many of New York’s smaller towns and villages may need greater support crafting a law that works for their community. To this end, a model code can serve as a measure that could be implemented as-is, or tweaked to fit local conditions. (Here, it is critical to note that the Accessory Homes Act would not impose a one-size-fits-all zoning code on every locality in New York. Rather, it directs localities to ensure that New Yorkers who wish to downsize, live with a caretaker, or bring in extra income are able to do so—while leaving significant flexibility on the appearance, placement, and number of ADUs they allow.) With the passage of A. 4854, New York’s towns and villages would receive assistance from the State that they might not otherwise. 

The bill is, to be sure, a level of state action that Albany has not taken in recent decades; but it’s similarly critical to remember that that recent baseline is by far the lowest of our peer states. As a recent Furman Center report finds, 

New York stands alone among its peer states—i.e. coastal states with high housing costs and healthy regional economies—in giving its local governments such broad authority over local land use… only New York has no statutory tool to promote land use reform and housing production in its suburban communities. The result is a state with fewer homes, more expensive rents, and starker segregation than it would otherwise have.

Acting to legalize ADUs would be a far cry from ending ‘local control’ in New York; it would not even bring the amount of authority that the state government asserts on land use matters up to the level that our neighboring states do.

The benefits of legalizing and providing funding for basement apartments, in-law units, garage conversions, and other accessory homes are clear and widespread. New York has an opportunity to act—creating affordable housing, providing extra income, and integrating our state’s communities, all with one well-crafted policy.