Carbon Monoxide Detectors Required

Puget Sound Energy's Energywise publication that comes with one's bill indicates the following:

The 2013 law requires carbon monoxide detectors in apartments, condos, hotels, dormitories and residential institutions. Owners of single-family homes built before 2009 will be required to have the detectors when their home is sold or when they apply for a remodeling permit. Carbon monoxide is a poisonous, colorless, tasteless gas, emitted by improper venting of fuel-burning equipment.

We have one in our bedroom secured to the wall. Just have to replace the battery once in a great while.