Here what the Washington Boater's Guide says:

"Since May 1, 1995, boats less than 16 feet long must have a WEARABLE PFD on board for each person. This includes canoes and kayaks. Type IV cushions or ring buoys do not meet this requirement."

You can get a Washington Boater's Guide from:

Boating Safety Program
Washington State Parks
7150 Cleanwater Lane
Olympia, WA 98504-2654
(360)902-8551

Hope this helps you out!
_________________________
Carl C.