There is broad support to allow accessory dwelling units, duplexes and triplexes in residential neighborhoods, according to a new Zillow survey covering 26 U.S. metro areas. A clear majority of homeowners surveyed (73 percent) voiced support for at least one of these “modest densification” options, and support was higher among renters (84 percent).

Rapidly rising rents and home values have pushed housing affordability to the center of the conversation in much of the country. Record-low inventory, triggered by a lost decade of home construction that caused a shortfall of 1.35 million new homes in 35 metro areas alone, has met a massive wave of demand, fueling an ultracompetitive market and pushing housing costs to crisis levels in some markets.

There is no easy fix, but building more homes is likely the most effective tool to rein in price growth. Zillow research has shown that modest densification measures—allowing two units on 10 percent of single-family lots across some of the largest U.S. metros—could help boost critically needed housing supply enough to meaningfully slow housing price growth. This survey shows a growing consensus among homeowners and renters that similar measures should be taken in their own neighborhoods to address affordability. 

Across the 26 metro areas Zillow surveyed, residents were more likely to support allowing accessory dwelling units (69 percent supported versus 23 percent opposed) and duplexes and triplexes (61 percent supported versus 31 percent opposed) in every single metro area.

Zillow Survey Finds Broad Support for Missing-Middle Housing in Major Metro Areas