Carbon Monoxide Alarm Requirements

All residential structures in the state of Wisconsin are required to have working Carbon Monoxide (CO) Detectors. As of February 1, 2011 every residential structure (new and existing) is required to be compliant with Administrative Codes SPS 321 (PDF) and 328 (PDF) of Wisconsin State Law. This law requires single family, duplexes and multifamily units (apartments/condos) to install and maintain working CO Detectors.

Multifamily Residential Structures
Apartments or Condos where 3 or more units share a roofline are considered “commercial” properties and receive regular fire inspections. Those structures are also required to have operational CO Detectors. Our fire inspectors work closely with the owners of these properties to ensure compliance.

Single & 2 Family Homes
If the structure has any of the following, a CO Detector is required on each level of the structure:
  • Any fuel burning appliance (stoves, ovens, clothes dryers)
  • Any fuel burning heater, furnace, boiler, water heater or fireplace
  • An attached garage or parking area
  • Placement of the CO Detectors shall be near sleeping areas where possible
  • New Construction must have CO Detectors that are hard-wired and have a battery back-up
  • Installed detectors must bear the listing of an independent testing lab (e.g. UL, ETL, FM)
  • If the structure does not have ANY fuel fired appliances, then a CO detector is not required
  • CO Detectors are not required in the following areas:
    • Attached or detached storage areas
    • Garage
    • Unfinished Attic
More Information
If you have further questions on CO, CO Detectors, or the state requirements please contact 1 of our fire inspectors:
  • Mark Mlekush
    Fire Inspector
    Ph: 608-837-5066
  • Michael Seltzner
    Fire Inspector
    Ph: 608-837-5066