A cousin of mine has been sitting on a two-flat in Logan Square for about eight years. He lives upstairs, rents the first floor, and every Thanksgiving he mentions the same idea: ""I want to build something in the back for my mom.""
Every year, the answer was the same. Zoning won't allow it. Not in his area.
This year, that answer might change.
Something Shifted This Month
Governor Pritzker just introduced the BUILD Illinois plan — a $250 million commitment to housing across the state. The short version: Illinois is short about 142,000 housing units, and the state needs to add over 225,000 in the next five years. That's not a projection someone made up. That's the gap between where we are and where we need to be. (Source: Chicago Agent Magazine, Feb 2026)
The money breaks into three buckets. $100 million goes to the Illinois Housing Development Authority for building middle housing — duplexes, triplexes, four-flats. $50 million goes toward down-payment assistance for first-time buyers. And $100 million goes to cities and towns to fix the infrastructure problems — sewer, stormwater, permitting backlogs — that keep housing from getting built even when zoning allows it. (Source: Chicago Agent Magazine, Feb 2026)
The Illinois REALTORS Association backed it immediately. They've been pushing for something like this for six years.
But the part that matters most for Chicago homeowners isn't the state plan. It's what the city is doing on April 1st.
April 1st Changes the Map
Right now, about 12% of Chicago is zoned for accessory dwelling units — ADUs. That's coach houses, basement apartments, attic conversions, detached backyard units. Starting April 1st, that number jumps to 29%. (Source: Abundant Housing Illinois ADU FAQ)
If you're not sure what an ADU is, think of it this way: it's an additional living space on your existing property. Your house stays your house. But now there's a separate unit — maybe above the garage, maybe in the basement, maybe a small building in the back — that someone can live in. Your mom. Your adult kid getting started. A tenant paying rent that covers a chunk of your mortgage.
Cities like Portland and Minneapolis have had these for years. Chicago ran a pilot program starting in 2021 in five small areas. Over 430 units got permitted. The demand was real. Now the city is opening it up much wider.
The newly eligible zones include all multifamily residential areas, mixed-use business-residential zones, and any single-family zone where your alderperson opts in. That last part is key — if you're in a single-family zone outside the original pilot areas, it depends on your alderperson. Some have already opted in. Others haven't yet.
The Tax Question Everyone Asks
My cousin's first concern wasn't construction or permits. It was taxes. ""If I build something back there, does my whole block get reassessed?""
Fair question. And the answer is no.
Cook County Assessor Fritz Kaegi has been clear about this: building an ADU on your property does not cause higher assessments for your neighbors. Their assessment is based on their property. Not yours. (Source: Abundant Housing Illinois ADU FAQ)
Now — your assessment will likely go up if you add livable square footage. That's how it works. You've made your property more valuable. But here's the part most people miss: there's a Home Improvement Exemption that can offset a portion of that increase for up to four years. You don't eat the full bump right away. You've got a window to let the rental income catch up to the cost. (Source: Abundant Housing Illinois ADU FAQ)
That changes the math for a lot of families.
What This Actually Looks Like in Real Dollars
Let's make it practical. Say you own a home on a decent-sized lot in one of the newly eligible zones. You build a small detached unit in the back — nothing fancy, maybe 600 square feet. Your property value goes up, but you've got four years of partial tax relief. Meanwhile, a modest one-bedroom rental in a Chicago neighborhood can pull over a thousand dollars a month, depending on the area. Even on the conservative end, that's meaningful annual income from a property you already own. Not a second property with a second mortgage and a second set of headaches. Your property. Your backyard.
Some families will use that to pay down their mortgage faster. Some will use it to help a parent age in place close by instead of across town in a facility. Some will just like having the option.
The BUILD plan also eliminated mandatory parking requirements within a half-mile of major transit hubs. That matters more than it sounds. Building a single parking space in Chicago can cost tens of thousands of dollars. When that requirement goes away, the math on smaller housing projects tilts from ""not worth it"" to ""this actually pencils out."" (Source: Chicago Agent Magazine, Feb 2026)
You Don't Have to Do Anything Right Now
Here's the thing — I'm not telling you to build an ADU. I'm telling you to understand what just changed.
If you own a home in one of the newly eligible zones, you have options today that you didn't have six months ago. That's worth knowing even if you never act on it. When your neighborhood's zoning shifts, it changes what gets built around you over the next five to ten years. It changes how your block looks, what the housing stock offers, and what your property means in the context of the neighborhood.
The families who understood the 2021 pilot early were the ones who moved on it first. The families who understand what April 1st, 2026 means will be positioned the same way. Not because they're speculators. Because they paid attention.
Here's What I'd Do If I Were You
First — check whether you're in the expansion zone. The city has mapped the eligible areas. If you're in multifamily or mixed-use zoning, you're already in. If you're in a single-family zone, look up whether your alderperson has opted in or is likely to.
Second — if the idea even slightly interests you, find someone who's been through the process in one of the pilot areas. Not a contractor trying to sell you a project. A homeowner who did it. Ask what the permit timeline looked like. Ask what they wish they'd known. Ask what it actually costs versus what they expected.
Third — don't panic and don't rush. The zoning change is real. The state money is real. But this isn't a ""buy now or miss out"" situation. It's a shift in what's possible. Understanding that shift puts you ahead of most homeowners in the city, and you can decide on your own timeline whether it makes sense for your family.
My cousin still hasn't built anything. But he's gotten his site surveyed, talked to a contractor, and actually understands his options now. That's all I suggested he do. Get to clarity first, then decide.
You can do the same.
Liked this? There's more at boydehomes.com. And if you want to understand how changes like this connect to your home's long-term value, the free Home Value and Equity Guide is a good place to start.
