New Rules for Carbon Monoxide Alarms

Last month’s snow, ice and wind gave us a timely reminder about the dangers of carbon monoxide poisoning during winter power outages. Following our 2006 windstorm, 250 people were treated for carbon monoxide (CO) poisoning in the Puget Sound area and eight died, all from either burning charcoal briquettes inside their homes or from improper use of gasoline-powered generators.

In response to these tragedies, new state-wide codes will require CO alarms in most residential buildings, including single-family homes. These rules are being implemented in stages:

  • Right Now: CO alarms are already required for all new hotels, apartments, condos and houses (R-1, R-2 & R-3) if they have attached garages or fuel-fired heat sources (such as gas furnaces or gas water heaters).
  • April 1 – All New Houses and Apartments: Permits filed beginning April 1, 2012 for new apartments, condos and houses will require CO alarms even for buildings that don’t have attached garages or fuel-fired heat sources. This is because far more poisoning cases result from improvised cooking and heating during power outages than from malfunctioning furnaces or idling cars.
  • January 1, 2013 – Existing Apartments and Rental Houses: State law requires all covered residential units to have CO detectors installed by January 1, 2013, just 11 months from now. Permit applications for alterations to existing single-family and multi-family dwellings must demonstrate that the CO detectors are already in place or include them as part of the project. (This requirement is not triggered by exterior finish work, plumbing, or non-combustion mechanical equipment.)
  • Owner-Occupied Single-Family Houses: Existing single-family homes that are owner-occupied are exempt from the January 1, 2013 deadline, but they are still required to include CO alarms in any building permit application for interior alterations. When the house is sold, state law also requires that CO alarms be installed before the new owner takes occupancy.
  • Hotels, Dorms and Institutions: Sleeping rooms in hotels, motels, dormitories, DSHS-licensed boarding homes and residential treatment facilities do not require CO alarms if the sleeping rooms are properly isolated from any fireplace, fuel-burning appliance or attached garage, and if there are CO alarms in the building’s common areas. (If these units contain or are connected in some manner to fireplaces, fuel-burning appliances (gas furnace, water heater, range) or attached garages, this exception would not apply.)

How to Comply

Simply install the CO alarms in the area right outside of each bedroom, with at least one alarm on each floor of the dwelling. They cost $30 to $50 at local hardware stores, and you can choose a model that runs entirely on batteries or a plug-in model with battery backup. Combination smoke alarm/CO alarm units are also available.

These new code provisions were developed with input from medical professionals, building operators, engineers and other experts to effectively prevent carbon monoxide poisonings while minimizing cost and disruption to owners and tenants. As more and more homes and apartments are fitted with CO alarms, the frequency of carbon monoxide poisonings in our community should decrease dramatically.

Read the full text of the state law at:

Read the Proposed Rule Making at:

Questions? Submit your questions to DPD’s Online Q&A Service:

Duane Jonlin
Energy Code & Energy Conservation Advisor