# Washington — Which energy code each US state enforces for new homes: the IECC edition (or state equivalent) actually in force, with effective dates and amendments, from the state rules themselves

For Washington, energy code in force is 2021 EDITION OF THE INTERNATIONAL ENERGY CONSERVATION CODE, RESIDENTIAL; state amendments is ADOPTION AND AMENDMENT OF THE 2021 EDITION OF THE INTERNATIONAL ENERGY CONSERVATION CODE, RESIDENTIAL; statute / rule citation is WAC 51-11R, verified against its source on 2026-08-18.

- **State:** Washington _(verified: appears in the quote below)_
- **Energy code in force:** 2021 EDITION OF THE INTERNATIONAL ENERGY CONSERVATION CODE, RESIDENTIAL _(verified: appears in the quote below)_
- **State amendments:** ADOPTION AND AMENDMENT OF THE 2021 EDITION OF THE INTERNATIONAL ENERGY CONSERVATION CODE, RESIDENTIAL _(verified: appears in the quote below)_
- **Statute / rule citation:** WAC 51-11R _(verified: appears in the quote below)_

## What the source says

> STATE BUILDING CODE ADOPTION AND AMENDMENT OF THE 2021 EDITION OF THE INTERNATIONAL ENERGY CONSERVATION CODE, RESIDENTIAL

## Source

- https://apps.leg.wa.gov/wac/default.aspx?cite=51-11R

Last verified: 2026-08-18. Review by: 2027-02-14.
Part of [Which energy code each US state enforces for new homes: the IECC edition (or state equivalent) actually in force, with effective dates and amendments, from the state rules themselves](https://referencesource.org/energy-code-adoption-by-state/).