Exhaust Noise in Washington
Washington requires an adequate muffler and sets in-use 50-foot limits of 72–90 dBA; the oft-cited 95 dBA test applies only to pre-1986 vehicles.
Verified against primary sources · August 2026
What the law says
RCW 46.37.390 requires a muffler in good working order and bans cutouts. WAC 173-62-030 sets in-use 50-foot limits of 72–90 dBA by class; its 95 dBA/20-inch stationary figure applies to pre-1986 vehicles only.
Specific Limits
- Test
- in-use 50-ft limits 72–90 dBA (WAC 173-62-030); 95 dBA test applies to pre-1986 vehicles only
Frequently Asked Questions
Are exhaust noise legal in Washington?
What are the exact exhaust noise limits in Washington?
Street-legal exhaust noise picks
Gear that helps you mod without a ticket in Washington.
Measure your exhaust at the test RPM before a fix-it ticket does.
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