Washington State Carbon Monoxide Law

January 1, 2011, Washington State law required CO detectors to be installed in all new single family homes and residences, including condominiums, apartments, hotels, and motels.

The state law requires CO detectors be installed in existing condominiums, apartments, hotels, motels and single- family residences by January 1, 2013. 
 
Owner-occupied single-family residences, legally occupied before July 26, 2009, are not required to have CO detectors until they are sold. The seller of the home is now required to supply the residence with CO detectors before any other person legally occupies the home.

If your home does not currently have carbon monoxide detectors you will be required to install detectors when any major modifications, alterations, repairs or additions occurs. This includes HVAC, plumbing and electrical work.
 

Local code officials will check for compliance with the CO detectors installation requirements when a permit is required for new construction and most modifications, alterations, repairs or additions.

Carbon Monoxide Detector Installation Requirements

1. Alarms must be located outside of each separate sleeping area, in the immediate vicinity of the bedroom and on each level of the residence.
2. Single station carbon monoxide alarms must be listed as complying with UL 2034, and installed in accordance with the code and the manufacturer’s instructions.
3. Combined CO and smoke alarms are permitted.
   
   
   NOTE: Carbon Monoxide is a heavy gas. Most CO detectors need to be installed as low to the ground as possible. Always refer to the manufacture safety information when installing CO detectors in your home. More information can be found here: Washington State Carbon Monoxide Law