As the Boston suburb of Cambridge, Massachusetts, acted this week to allow a wide variety of home types in neighborhoods previously limited to single-family housing, Illinois is weighing a similar measure that would affect the whole state.
They join a growing number of cities and states that have begun allowing duplexes and small apartment buildings in areas where they hadn’t been permitted in decades, if ever.
Cambridge’s City Council voted Monday to allow residential buildings of up to six stories in these neighborhoods, at least twice the height of the typical single-family house. Meanwhile, a bill under review in Illinois’ general assembly would require cities with more than 25,000 residents to allow structures with multiple units on a residential lot.
Housing advocates support these types of measures because building more units increases the supply in a market, ideally driving down prices. But it can be difficult to get existing homeowners to support the greater housing density, especially when it involves changes in neighborhood character such as larger buildings.
Since 2019, Oregon, Maine, California, and Washington state have each ended the longstanding practice of limiting housing in certain neighborhoods to the single-family variety. The cities of Minneapolis; Portland, Oregon; and Berkeley, California have taken similar steps on their own. A few localities that approved these changes have become mired in court battles with neighborhood opponents, as in Arlington County, a suburb of Washington, D.C. California’s legal change survived a court challenge but has produced relatively few new homes to date.
Chapters of the national YIMBY, or Yes In My Backyard, movement have often led the effort to convince city and state officials to allow more housing. The response of neighborhood groups and legislators opposed to this varies but often involves concerns about whether local infrastructure can handle the increased housing density.
In overturning Arlington County's plan last September to allow more types of housing in single-family areas, a Virginia judge cited residents' concerns about new development putting a strain on stormwater and sewage infrastructure. The county said it would appeal the judge's ruling.
In Cambridge, a city of 118,000, City Councilor Burhan Azeem calculated on his X social media page that on a typical 11,000-square-foot lot where previously a single house was allowed, as many as 46 homes could be constructed under the new rules. The new zoning will produce thousands of new houses and apartments, he said.
“This is one of the biggest changes to any city’s zoning in decades. I’m hopeful Cambridge’s bold move will inspire other cities to act,” he said before he and his colleagues voted unanimously Monday to allow more homes in single-family areas.
Illinois takes varied approach
Illinois House Bill 1814, introduced in the General Assembly on Jan. 28, proposes to remove single-family zoning from municipalities with populations of 25,000 or higher on parcels greater than 5,000 square feet and allow multiple middle-density housing types. These include buildings with up to four units, townhouses and cottage clusters, which are single-acre groupings of at least four small-footprint homes. The bill also proposes that cities with populations between 10,000 and 25,000 allow duplex construction on previously zoned single-family parcels.
The proposal has support and collaboration from the Illinois Realtors Association, along with a bill that would require these cities and towns to permit accessory dwelling units. So-called ADUs can be detached structures on a lot, such as a coach house, or attached, such as an attic or basement unit.
ADUs are seen to be more affordable housing types due to their small footprint, and quick additions to housing stock since they utilize existing parcels or even existing structures, if attached. Many units are rented out, producing income for the property owner.
These bills are part of a package of five bills the group announced aimed at encouraging housing accessibility; the others include efforts to assist first-time homebuyers, create consistent impact fees, and ban crime-free housing ordinances.
Senate Bill 148 proposes the creation of the Illinois Homebuyer Savings Account Act that would provide tax deductions on money saved for a home purchase. Tax filers could receive up to $10,000 in yearly tax deductions.
Senate Bill 1959 aims to create uniform impact fees, which are paid by builders, developers, and property owners to a municipality. Illinois Realtors said that municipalities have applied higher fees outside of the state regulations, which impacts new construction efforts.
House Bill 3110 would end the ordinance that allows for eviction of tenants who’ve had contact with law enforcement.
Both efforts for accessory dwellings and single-family zoning bans have been tested in Chicago and the state in recent years, with former Chicago Mayor Lori Lightfoot’s ordinance in 2020 that allowed ADUs in five pilot zones in the city and a 2024 state bill that called for a single-family zoning ban for areas with populations of 100,000 and higher.
About 41% of Chicago’s land area is classified as single-unit residential, according to the Metropolitan Planning Council.
In Evanston, a suburb north of Chicago, talks of ending single-family zoning have been in the works since January 2024. It’s part of the city’s Envision Evanston 2045 initiative that would create new zoning codes and a comprehensive plan. A major part of the initiative is rezoning single-family zones to allow a minimum of four units. Evanston also permitted one accessory dwelling per residential lot in 2020.
Skepticism of outcomes
The changes Cambridge approved Monday were necessary for the city to avoid its housing becoming completely out of reach to middle-class buyers and renters, according to City Councilor Marc McGovern, who spoke to colleagues before the vote.
"We can't just be a community of folks who can afford $2 million homes and those who qualify for subsidized housing. That is not a healthy community," he said.
Proponents of the changes accommodated some skeptics on the city council by setting a 5,000-square-foot minimum for lots that will be eligible for larger buildings, the same floor Illinois legislators are considering. While she voted yes Monday, Councilor Catherine Zusy told colleagues she doubts the outcome of the vote will help many people with lower incomes afford to live in the city.
“I wish it wasn’t so, but I believe this proposal will produce mostly luxury units, raise real estate values and taxes and rents, displace residents, and cause psychological havoc in our neighborhoods,” she said. “It is a recipe for random development at the whim of developers.”