PHOTO: Accessory dwelling unit

A one-bedroom, one-bath accessory dwelling unit installed over a garage in Mt. Pleasant, S.C.

IN SOME cities where affordable housing is hard to find, public officials are looking at “infill development” to expand their housing stock. Infill development can range from shoehorning new homes into established neighborhoods, retrofitting vacant commercial buildings for residential use, or changing zoning ordinances to allow accessory dwelling units (ADUs) in single-family homeowners’ backyards.

In late June, the Oregon state Senate became the first in the nation to replace single-family residential zoning with residential zoning that allows ADUs as well as multi-family dwellings to be built in what were formerly detached single-family neighborhoods.

Seattle, Portland, Los Angeles and Austin have ADU-friendly ordinances. But they are the only major U.S. cities with more than 1,000 ADUs.



Opposition to ADUs comes mostly from homeowners, who view a proliferation of “granny flats” in the neighborhood as a threat to their property values. They fear that increased density will add to traffic congestion, overcrowded schools and public services, and all the other ills associated with unrestrained population growth.

However, ADUs can also provide those same homeowners with a steady source of rental income while providing relatively low-cost housing for seniors, the disabled, and workers whose annual income cannot keep pace with rising housing costs. In the greater Fredericksburg area, that includes 115,884 ALICE (Asset Limited, Income Constrained, Employed) households.

The region’s affordable housing shortage is exacerbated by the high cost of land, which does not encourage construction of moderately-priced homes. But proposals to do something about the affordable housing crisis usually center on government solutions, which require higher taxes. But higher taxes just add to the cost of a mortgage or rent, making housing even less affordable.

The Virginia Code allows jurisdictions to set up ADU programs to “address housing needs, promote a full range of housing choices, and encourage the construction and continued existence of housing affordable to low and moderate income citizens.”

In May, the Arlington County Board voted to relax its zoning regulations to allow ADUs to be installed without the county’s permission as long as they are at least five feet from the property line, have a separate entrance, their own kitchen and bathroom, and be no larger than 750 square feet.

But building and financing ADUs can be tricky.

“Building a free-standing, 250-square-foot ADU with a bathroom and compact kitchen can be as complicated as building an entirely new, three-story, 2,500-square-foot house,” Washington Post architectural columnist Roger Lewis points out, which explains why only 20 ADUs have been approved in Arlington over the past decade even though the median price of a single-family home there is up to $689,400.

Last August, Fredericksburg City Council member Jason Graham suggested that the council “begin a public dialogue” on the pros and cons of ADUs, which are not currently allowed in the city. If city officials are serious about fixing the city’s affordable housing crisis, ADUs would be a good place to start.