Accessory dwelling units are a key component of Bethlehem's strategy to increase housing supply, and the City of Bethlehem is amending the city’s ordinance to permit new construction of ADUs. They hired Woodsong Associates and Robert Liberty to work with them and the Small Cities Lab to review and update the zoning ordinance.

At the second Steering Committee meeting, the Small Cities Lab team presented a high-level timeline of the city’s zoning evolution from 1926 to today. The timeline reveals that Bethlehem has experienced periods of both up-zoning (increasing density or land-use flexibility) and down-zoning (restricting development or land use). Bethlehem zoning has not followed a consistent trajectory of down-zoning, highlighting a precedent of change depending on the perspectives and needs of the city at the time.

The team discussed three zoning measures and requirements often added to accessory dwelling unit amendments within zoning ordinances. The three most common measures are parking requirements, owner-occupancy, and unit types. The Small Cities Lab completed 314 case studies examining zoning measures related to ADUs in small cities across the country.

The most debated topic in permitting accessory dwelling units is the regulation of parking–more than half of the studied cities require additional parking when adding a second unit. However, some of the cities that generally require additional parking also have notable exceptions: if a home is in close proximity to public transit, they are exempt from additional parking requirements. This conversation on parking at the steering committee meeting sparked questions about whether the exceptions are allowed by-right (without needing special approval) or require a variance from the zoning board. Sara Satullo, the Deputy Director of Community Development at the City, raised this issue, which is currently being examined in Bethlehem’s proposed zoning reforms.

Zoning measures also affect who can occupy them and what type of unit can be constructed. One key consideration for ADU zoning inclusion is whether the primary residence must be owner-occupied, a rule that could limit potential tenants or owners. Additionally, some cities implement requirements for design and type of building allowed as an ADU, stating that new accessory buildings must align with the current design of the neighborhood. Bethlehem, however, does not have a cohesive design aesthetic, and regulations on building design have historically been broad and subjective. This has made it difficult to impose strict design guidelines without adding significant costs to homeowners. In fact, some city officials and planners argue that requiring a uniform style for ADUs is not a best practice. Since it’s nearly impossible to pinpoint when new units were added to a city, focusing on design replication could hinder the flexibility needed to foster diverse housing solutions.

On top of 314 general case studies, the Small Cities Lab is completing in-depth analysis of ten cities that share size and characteristics to Bethlehem, including Ann Arbor, Michigan, and New Haven, Connecticut. These case studies provide valuable insights into how the different zoning measures have played out in other regions, and if they have generally hindered or enabled new construction. The Steering Committee will use this research and consider these extra measures, supporting the City as it moves forward with zoning reform.