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McHenry County, IL Fire Regulations: Smoke Detectors (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Placement
Within 15 ft of bedrooms
Coverage
Every story incl. basement
Battery since 2023
Sealed 10-year
Landlord duty
Supply and install
Fine
Up to $100

Summary

Illinois law requires a working smoke detector within 15 feet of every sleeping room and on every story of a home, including basements. Since January 1, 2023, newly installed alarms must have sealed 10-year batteries.

These county ordinances apply to unincorporated areas of McHenry County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

Every dwelling unit or hotel shall be equipped with at least one approved smoke detector in an operating condition within 15 feet of every room used for sleeping purposes. Every single family residence shall have at least one approved smoke detector installed on every story of the dwelling unit, including basements but not including unoccupied attics.

Full Breakdown

The Smoke Detector Act (425 ILCS 60/3) applies statewide, including McHenry County. Every dwelling unit must have at least one approved smoke detector within 15 feet of every room used for sleeping, and every single-family residence must have one on every story, including basements but excluding unoccupied attics. As of January 1, 2023, any newly purchased or installed alarm in a home without hardwired or wireless-integrated alarms must use a non-removable, non-replaceable 10-year sealed battery. Homes with hardwired or low-voltage alarms are exempt from the sealed-battery mandate. Landlords supply and install the alarms; tenants test and maintain them.

Violations & Fines

Owners who fail to provide compliant alarms may receive a 90-day notice to comply and, after that period, fines of up to $100 per violation.

Frequently Asked Questions

Do I need 10-year sealed-battery smoke alarms?
Newly installed alarms in homes without hardwired or wireless-integrated alarms must have sealed 10-year batteries since January 1, 2023; existing compliant alarms can stay until they expire or fail.
Where must smoke alarms be placed?
At least one within 15 feet of every sleeping room, plus one on each story of the home, including the basement but not unoccupied attics.

Sources & Official References

Other rules in McHenry County

All McHenry County rules

Compare McHenry County to another location·View the Illinois fire regulations overview

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