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
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.
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