Smoke and Carbon Monoxide Alarms in Illinois: What Sellers Should Check Before Listing and Buyers Should Check Before Moving In

Fall is when the furnace kicks on, the windows close, and a lot of Chicagoland homes hit the market or change hands. It's also the perfect time to look up at your ceiling. Smoke and carbon monoxide alarms are small, cheap and easy to forget, but Illinois has specific rules about them, and they're one of the first things a buyer, an inspector or a village inspector will notice.

The smoke alarm basics in Illinois

The Illinois Smoke Detector Act says every dwelling unit needs at least one working smoke detector within 15 feet of every room used for sleeping. It goes on the ceiling at least 6 inches from any wall, or on a wall between 4 and 6 inches from the ceiling. (425 ILCS 60/3)

For a single-family house, the law also requires at least one detector on every story, including the basement (unoccupied attics don't count). In a building with more than one unit, like a two-flat, a three-flat or a condo building, there also has to be a detector at the top of each interior stairwell.

The 10-year sealed battery rule

This is the part a lot of homeowners missed. Since January 1, 2023, any new battery-powered smoke alarm installed in an Illinois home has to have a 10-year sealed battery, the kind you can't pop out. (Illinois State Fire Marshal)

You don't have to rip out every older alarm today. According to the State Fire Marshal, alarms that were already in place can stay until they're more than 10 years past their manufacture date, fail a test or otherwise stop working. At that point, the replacement has to meet the new rule.

There are exemptions. Homes built after 1988 that already have hardwired alarms are covered, and so are alarms that connect wirelessly through a low-power radio signal or Wi-Fi. Alarms tied into a centrally monitored alarm system are exempt from the battery rule too.

A practical tip: the manufacture date is usually printed on the back of the alarm. Twist it off the base, check the date, and you'll know quickly whether it's time.

Carbon monoxide alarms

Illinois also has the Carbon Monoxide Alarm Detector Act, in effect since January 1, 2007. It requires at least one working CO alarm within 15 feet of every room used for sleeping. The alarm can be battery powered, plug-in with battery backup, or hardwired with battery backup, and it can be a combination smoke and CO unit as long as it clearly tells you which hazard it's sounding for. (430 ILCS 135/10)

The State Fire Marshal explains that the requirement applies to homes that burn fossil fuel for cooking, heat or hot water, or that are connected to an enclosed garage. In Chicagoland, with all the gas furnaces, gas water heaters and attached garages, that covers a lot of homes. The Fire Marshal also suggests keeping CO detectors away from the kitchen, the garage and the furnace room. (Illinois State Fire Marshal: CO detectors)

Sellers: a 20-minute pre-listing check

Before photos and showings, walk the house with a step stool:

• Make sure there's a smoke alarm near every bedroom and on every level, including the basement.
• Check the manufacture date on each alarm. Anything over 10 years old should be replaced, and battery-powered replacements need the sealed 10-year battery.
• Confirm a CO alarm is within 15 feet of each sleeping area.
• Press the test button on every unit. A chirping alarm during a showing doesn't leave a great impression.

Some towns go further. A number of Chicago suburbs require a village inspection before a sale, and alarms are a common item on those checklists, so it pays to look up your town's rules early. Your home inspector or local building department can tell you what applies.

Buyers: check on move-in day

Moving day is busy, but put this near the top of the list. Test every alarm, look at the dates, and replace anything old or missing. If your inspection report flagged missing or expired alarms, your attorney can raise it during attorney review. Often it's an easy fix that the seller handles before closing.

Condo and multi-unit owners

In a building with more than one unit, the law puts the job of supplying and installing the required alarms on the owner of the structure. Inside a rented unit, the tenant handles testing and battery replacement, though the owner has to make sure the batteries work when the tenant moves in. If you own a condo, check your association's rules for common areas and stairwells, and take care of the alarms inside your own unit.

The bottom line

Smoke and CO alarms are one of the cheapest, easiest items on any home sale checklist, and they protect the people living there. Get them right before you list, or right after you get the keys, and it's one less thing to worry about.

Buying or selling anywhere in Chicago or the suburbs? Call or text me at 312.882.9797. I'll help you get the details like this handled, along with everything else. Full-service real estate, lower commission.

This article is general information, not legal or safety advice. Local codes can add requirements, so check with your municipality, a licensed inspector or a real estate attorney about your specific home.