The City of Madison Fire Department encourages everyone to learn more about Wisconsin’s carbon monoxide (CO) law.


  • All single-family and two-unit homes – new and existing – must install a CO alarm on every floor level near sleeping areas.
  • New construction must be hard-wired with a battery back-up.
  • Existing homes may install any type of CO alarms: battery, plug-in, or combination smoke/CO devices.
  • A carbon monoxide detector required under this section shall bear an Underwriters Laboratories (UL), Inc. listing mark.
  • Alarms should be installed in accordance with directions from manufacturer.


CO alarms are only required in new and existing homes that have any fuel burning appliances such as stoves, ovens, grills, clothes dryers, furnaces, boilers, water heaters, fireplaces, and heaters, OR an attached garage.

Alarms do not need to be installed in the attic, garage, or storage area of homes.


  • Test alarms monthly.
  • Replace alarms according to manufacturer instructions.
  • Check batteries and replace twice a year.
  • Alarms should never be disconnected or unplugged.
  • Batteries should never be removed for other uses.

This information based on Wisconsin Act 158 and Wisconsin Department of Commerce Rules.