The code is listed by numbered years. Earlier editions of RCW and its predecessors, as far back as the Code of 1881, are available at the State Law Library.
The Washington Administrative Code (WAC) is a compilation of the regulations of executive branch agencies, which are issued by authority of statutes. Like legislation and the Constitution, regulations are a source of primary law in Washington State. The WAC codifies the regulations and arranges them by subject or agency. A new edition of the WAC is issued every two years with supplements issued each year between new editions.
Both the RCW and the WAC can be viewed from the Statute Law Committee website. Additionally, many local libraries maintain these books in their reference sections, and they can be found at the Washington State Library in Olympia.