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Washington: Cannabis Laws (Adult-Use, Medical & DUI/THC Rule)

Plain-language guide to Washington State cannabis laws—adult-use, medical program (DOH), retail (WSLCB), and DUI/THC per se statute—with official links.

Washington State: Cannabis Law Overview

Last updated: October 14, 2025

Disclaimer: This page is informational only and not legal advice. Laws change quickly. Always verify on official state portals linked below and follow the strictest applicable rule. See our Legal Disclaimer & No-Warranty and Terms of Use.

Snapshot

  • Adult-use (R): Legal; retail licensing and enforcement by the Washington State Liquor & Cannabis Board (WSLCB).
  • Medical (M): Administered by the Washington Department of Health (DOH); patient registry, endorsements, and product standards.
  • DUI/Impairment: Washington enforces a per se THC limit for driving—see the RCW reference below and DOH/WSLCB resources.

Official Portals & Statutes

Practical Notes (Orientation)

  • Possession & purchase limits are defined in statute and rule; always verify on WSLCB/DOH before purchase.
  • DUI/THC per se: Washington law includes a numeric THC limit (blood ng/mL within two hours of driving). Do not drive while impaired or within windows where impairment is possible.
  • Medical benefits: DOH-endorsed stores and patient registration may affect purchase limits/taxes. Check DOH guidance for eligibility and protections.
  • Local rules: Some municipalities add zoning/time-place-manner rules for retail. Check local notices when applicable.

Related Reading on 420.place

Travel & Federal Property Reminder

Do not carry cannabis across state or national borders, or onto federal property (airports, national parks, federal buildings). Federal law applies regardless of state programs.

Scientific Sources & References

All information in this article is backed by credible scientific sources and research studies.