Boiler laws & rules

The Washington Administrative Code (WAC) Chapter 296-104 WAC and Revised Code of Washington (RCW) Chapter 70.79 RCW cover boilers and pressure vessels. The laws and rules are maintained and updated by the State Office of the Code Reviser (

Download and print our Boilers and Unfired Pressure Vessel Laws Book (1.1 MB PDF) (updated 5/2018).


Rule development

2018 rule changes

The Board of Boiler Rules and Washington State Department of Labor & Industries is proposing changes to the boiler rules to adopt new safety code requirements, update and clarify existing rules, and increase fees by 4 percent. The changes would affect "Washington Administrative Code 296-104, "Board of Boiler Rules Substantive" (

Proposed amendments to this chapter will:

  • Amend the definition of "hot water heater" to clarify existing requirements.
  • Replace the "A" endorsement with authorized inspector commission to align with National Board Inspection Code (NBIC), NB-263 RCI-1 for inspector commissions and endorsements.
  • Amend language to align with NBIC, current edition, Part 4 for installation, inservice inspection, and repair of pressure relief devices.
  • Adopt the NBIC, current edition, Part 1, as the standard for installation of non-nuclear boilers, unfired pressure vessels and safety devices.
  • Clarify the duties of in-service inspectors in relation to other standards and requirements for which other regulatory agencies have authority or responsibility.
  • Adopt the Uniform Plumbing Code (UPC), Section 608.5 with Washington State amendments as discharge piping requirements for water heaters.
  • Replace Supplement 10 with Supplement 7 for nonnuclear repairs and alterations to align the rule with the NBIC, current edition, Part 3.
  • Increase fees by the fiscal-growth factor of 4% to cover operating expenses.

The following are documents on rulemaking:

What happens next?

  • September 18, 2018: Proposed rules (CR-102) filed with the Code Reviser's Office.
  • November 13, 2018: Written comment period on proposed rules ends at 11 a.m.
  • November 14, 2018: A public hearing on the proposed rules is scheduled for 10 a.m.. The meeting will take place at the L&I Tacoma building, 950 Broadway, Suite 200, Tacoma, WA.
  • November 2018: Expected filing of final rules (CR-103) with the Code Reviser's Office.
  • January 1, 2019: Expected effective date of the rules.

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