Washington law
Environmental Laws in Washington.
Washington environmental law is administered principally by the Department of Ecology under authority of the State Environmental Policy Act (SEPA, RCW 43.21C) and specific pollution-control titles. SEPA is Washington's NEPA-equivalent and requires environmental review before most state and local agency actions. The Model Toxics Control Act (MTCA, RCW 70A.305) is Washington's state-law Superfund statute — one of the most assertive state hazardous-waste-cleanup regimes in the country. Washington also operates a cap-and-invest program under the Climate Commitment Act (RCW 70A.65).
Last verified: 2026-04-20
Guided help
Ask about a environmental law deadline, right, or next step.
Keep the question grounded in Washington. FlowLawyers can route you to the statute section, legal aid, attorney search, or a guided workflow when one fits.
Fast paths
The law sections below preserve the citations and source links. Use guided help when you need to move from reading the rule to choosing what to do next.
State law
Key Washington Statutes
Washington's NEPA-equivalent — requires environmental review before state and local agency decisions that may have a probable significant adverse environmental impact.
Washington's state-law Superfund statute — administered by Ecology, imposes strict, joint, and several liability on owners/operators of hazardous-waste sites with a private cost-recovery remedy.
Washington's 2021 cap-and-invest program — establishes a declining cap on greenhouse-gas emissions and an allowance auction market. Largely upheld by Washington voters in 2024.
Washington's principal water-pollution-control statute, with a state NPDES-equivalent permit program administered by the Department of Ecology.
State law
Official Sources
Not Legal Advice
This page summarizes publicly available statutes and rules for informational purposes only. It does not constitute legal advice, and no attorney-client relationship is created by viewing this content. Laws change — always verify with the primary source or consult a licensed attorney in Washington.
More in Washington
Other state law topics.
Personal Injury Laws·Criminal Defense Laws·Family Laws·Immigration Laws·Employment Laws·Bankruptcy Laws·Medical Malpractice Laws·Workers' Compensation Laws·Social Security Disability Laws·Wrongful Death Laws·Product Liability Laws·Long-Term Disability & ERISA Laws·Estate Planning Laws·Probate Laws·Real Estate Laws·Landlord & Tenant Laws·Business Laws·Intellectual Property Laws·Tax Laws·Elder Laws·Nursing Home Abuse & Neglect Laws·Civil Rights Laws·Domestic Violence Laws·Veterans Legal Services Laws·Healthcare & Benefits Laws·Construction Defect Laws·Insurance Disputes Laws·Premises Liability Laws·Commercial Litigation Laws·Securities & Finance Laws·Municipal Laws·Administrative Laws