Elisabeth Haub Law School of Law
Pace University
Land Use Law Center
Supervisor: John R. Nolon, Distinguished Professor
Blog No. 22 of the Land Use, Human Health, and Equity Project
Editor: Brooke Mercaldi
Contributing Author: Bailey Andree [*]


NIMBY Restrictions Poison the Prospects of Accessory Dwelling Units to Address Housing Insecurity


The previous blog “Housing, a Crucial Determinant of Health” defined and discussed the seriousness of housing insecurity, one of the four pandemics evaluated by the Land Use, Human Health, and Equity project at the Land Use Law Center. Relatedly, as discussed in “ADU Introduction,” Accessory Dwelling Units (ADUs) are a promising new trend in the national search for solutions to the housing crisis. Local land use laws that allow ADUs open the vast single-family zoned urban landscape to additional housing development. In many communities, however, neighborhood opposition has poisoned the promise of the ADU solution by raising concerns that limit what kinds of ADUs may be created.


Not In My Backyard, or NIMBYism, discourages new development, including ADUs, to protect existing neighborhood character. Many of NIMBY’s proponents – often middle and upper class households – see affordable housing development as bringing an undesirable change into the community and argue that this change will depress property values and increase crime, litter, and violence in the neighborhood. The result of NIMBY opposition to ADU development poisons the prospects of a robust embrace of ADUs as a response to the need for affordable residences in safe neighborhoods.


Where NIMBY provides the political opposition, poison pills provide the legal means to prevent affordable housing development. The term “poison pill” derives its meaning from the poison pills spies would carry in case of capture. Planners began referring to ADU restrictions as poison pills to showcase how the regulations can “effectively kill” the ADU development.  There are many types of poison pills used to prevent and limit ADU construction. The most common, with examples, include:


  1. Owner occupancy requirements. SeaTac, WA requires the primary residence to be occupied by the owner in order to build and rent out an ADU.
  1. Maximum size requirements. Norwalk, CT does not allow ADUs greater than 700 square feet.
  2. Off-street parking requirements. SeaTac, WA requires two off-street parking spaces for ADUs over 600 square feet.
  3. Occupant requirements. West Hartford, CT previously required ADU occupants to be domestic workers for or the family of the primary residence owner. This has been repealed.
  4. Age and disability requirements. Fairfax, VA requires either an ADU or primary residence occupant to be elderly – at least 55 years old – or “permanently and totally disabled.”
  5. Restrictions on the number of occupants. Newton, MA does not allow the ADU to increase the maximum number of residents permitted beyond what was allowed for a principal dwelling unit alone.
  6. As-of-right designations. Raleigh, NC previously prohibited ADUs from being permitted as of right in residential zones, significantly limiting ADU development.


To eliminate some of these poison pills, municipalities such as Raleigh, NC have reduced ADU restrictions to address the affordable housing crisis. Raleigh previously restricted ADU construction to one specific overlay zone, did not allow ADUs as of right in any residential zone, and required residents to petition their neighbors when seeking to develop ADUs on their property. Now, Raleigh allows ADUs as of right in all residential zones without any significant restriction on their construction or subsequent use. This promotes affordable housing and encourages diversity in both housing stock and occupancy. Seattle, WA recently enacted zoning legislation that removes significant barriers to ADU development in order to address the city’s housing crisis. The new code removes off-street parking and owner occupancy requirements while also streamlining the approval process for ADU development. Seattle also created a user-friendly website to simplify the process for its residents by connecting homeowners considering ADUs to members of the design and construction community, and it even addresses the high cost of ADU development through access to low-interest financing. Techniques such as these will provide much needed momentum in the ADU process, more effectively addressing the housing insecurity pandemic.


On the state level, Connecticut recently passed a bill that promotes development of ADUs. HB 6107 legalizes ADUs in the state and removes off-street parking requirements. This bill allows ADUs as of right on all properties that contain at least one single-family home. It also prohibits municipalities from implementing several restrictions on ADU development, including minimum age and occupant relationship requirements. Oregon also recently passed HB 2001 addressing ADU creation. The state now requires cities with populations greater than 2,500 or counties with populations greater than 15,000 to allow for ADUs in all single-family zones.


By following those suggestions to implement solutions like Raleigh, Connecticut, or Oregon, municipalities can combat NIMBYism and promote development of ADUs. The national housing crisis demands it.


For additional resources, the Gaining Ground Information Database is free and features best practice models used by governments to control the use of land in the public interest. Please direct your search toward the Healthy Communities topic.


[*] Bailey Andree is a second-year student at the Elisabeth Haub School of Law, Student Associate at the Land Use Law Center, and Research Assistant to Professor Nolon.

Brooke Mercaldi is a second-year student at the Elisabeth Haub School of Law and Research Assistant to Professor Nolon.

The previous blogs in the series are listed here:

  1. Reframing Sustainability: Introducing the Land Use, Human Health, and Equity Project
  2. Planning for Public Health: A New Beginning for Land Use Law
  3. The Role of Density in Combatting Climate Change and COVID-19
  4. Novel Coronavirus Claims Implicate Age-Old Property Rights Questions
  5. State & Local COVID-related Emergency Powers: Individual Rights
  6. COVID-Related Land Use Regulations and Judicial Deference
  7. Mediation of Eviction Disputes May Hold the Key to the Survival of Small Businesses
  8. Using Zoning to Help Eliminate Food Deserts: A Few Steps Forward
  9. Urban Heat Islands and Equity
  10. Urban Heat Island and Equity: What Can Local Governments Do?
  11. The Recovery Lease: Preventing Evictions of Commercial Tenants During the Pandemic
  12. The Role of Hazard Mitigation Planning in Promoting Public Health and Resilience
  13. Hazard Mitigation Planning: A Case Study
  14. Complete Streets: Protecting Public Health
  15. Zoning and Lease Mediation as a Way to Retain Critical Small Businesses
  16. Segregation by Law and the Racial Inequity Pandemic
  17. Combating Food Swamps to Improve Equity and Public Health
  18. The Pandemic Plan for Healthy Buildings
  19. Remediating Distressed Properties to Improve Public Health
  20. Housing, a Crucial Determinant of Health
  21. ADU Introduction


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