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Washington Exhaust & Muffler Laws (2026)
Info: Your vehicle needs a muffler in good working order.
InfoVerified Jun 19, 2026
Vehicle rules change at the state line.Track them in the free LawLert iPhone app and get an alert when you cross into a state where they differ. No account.Get the appYour vehicle needs a muffler in good working order. Cutouts and bypasses (which route exhaust around the muffler) are prohibited, and so is exhaust amplified beyond the factory muffler. Washington sets no decibel limit in statute (RCW § 46.37.390).
Official source: app.leg.wa.gov →
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