The latest trend in assisted living — particularly amid the COVID-19 pandemic — may be something known as an accessory dwelling unit, or ADU, a broad term for a secondary housing structure built on the property of an existing home. 

Although auxiliary apartments, often nicknamed “granny flats” or “mother-in-law suites,” have been popular for decades, in recent years, urban planners have hailed them as a major solution to growing housing shortages for the country’s swelling senior population. The option is especially attractive in denser areas, where homes typically are expensive and unfit for people who might someday struggle with stairs and slippery bathtubs, according to a recent New York Times analysis.

Although the cost of building such a home for one’s parents is expensive, it is on a comparative basis less expensive than moving one’s parents into an assisted living community. The movement has been helped in recent years — at least in one state — by sweeping regulations in California, making the construction of the units more affordable. The coronavirus also has accelerated demand, as families look to quarantine together and often shun long-term care and other congregate-living settings. 

“The pandemic has forced people to look at nursing homes and ask themselves, ‘Do we need more housing options for older people?’ And the answer is yes,” Rodney Harrell, AARP’s vice president of family, home and community, told the media outlet. “We don’t have the right mix of available housing for older people with varying levels of needs, and A.D.U.s are a way to help us fill in those gaps.”