2018 Seattle Code Adoption - What & Why

What’s Happening Now?

The City Council recently passed an amendment to the 2018 Seattle Energy Code that extends the requirement for heat pump water heaters to non-residential commercial buildings. This amendment will take effect for permit applications submitted as of April 1, 2022.

For new construction, the changes to Section C404.2.3 clarify that the new requirements apply to commercial buildings with more than 15 kW of water heating capacity. The additional efficiency credits table (Table C406.1) is also modified to eliminate credit for option 8, and to reduce credit for option 9, since heat pump water heating will now be required in the base code. For existing buildings, the water heating requirements in Section C503.5 apply to substantial alterations projects and to projects in which a building's central water heating system is augmented or replaced. "Central" water heating systems are systems that serve multiple areas of a building, not individual water heaters that serve a single use.

The amendments include some important exemptions. The most significant exception is number 8, which allows a gas or electric resistance water heating system to be replaced in kind in an existing commercial building. Other exceptions include: an electric resistance water heater in a tenant space up to 15 kW capacity, a unitary heat pump water heater in a conditioned space, and systems in commercial buildings served by district steam systems. Note: These exceptions do not apply to hotel or multifamily buildings.

For further information, contact SDCI's energy code advisor Duane Jonlin, duane.jonlin@seattle.gov.

Seattle Codes Now Available

We have adopted the 2018 editions of the Seattle construction codes and have subsequently adopted errata to correct errors in the printing of the Building, Energy, and Boiler and Pressure Vessel Codes. Code changes can come from various sources including the International Code Council, State of Washington, members of the public, and City staff.

The Seattle codes are now available for purchase. See our Project Documents page for information about pricing and ordering instructions.

Project Benefits

Regular updates to Seattle's construction codes make it easier to:

  • Incorporate emerging technology and materials into construction to increase a building's safety, usability, and lifespan
  • Keep Seattle competitive and innovative with early adoption of national code changes
  • Adopt requirements that ensure Seattle's leading-edge energy and carbon reduction goals are met
  • Decrease differences in construction code adoption and enforcement with neighboring communities    

The End Result

Seattle adopted the 2018 editions of the national model codes published by the International Code Council along with State of Washington and local amendments. They became effective on March 15, 2021. Seattle adopted errata that went into effect on July 6, 2021 to correct printing errors. A summary of key changes is posted on the Project Documents page.