Exhaust Noise in Idaho
Idaho sets no statewide decibel limit for passenger cars. A muffler in good working order is required, exhaust may not produce excessive or unusual noise, and cutouts or bypasses are prohibited.
Verified against primary sources · August 2026
What the law says
Idaho law is qualitative rather than numeric: A muffler in good working order is required, exhaust may not produce excessive or unusual noise, and cutouts or bypasses are prohibited. Idaho also bans modifications above the original equipment level. Section 49-937(4) refers to exceeding 'the maximum allowable decibel level' as prima facie evidence, but no Idaho provision actually sets that number — treat any published Idaho decibel figure as unsupported.
Specific Limits
- Statewide decibel limit
- none
Frequently Asked Questions
Are exhaust noise legal in Idaho?
What are the exact exhaust noise limits in Idaho?
Street-legal exhaust noise picks
Gear that helps you mod without a ticket in Idaho.
Measure your exhaust at the test RPM before a fix-it ticket does.
Shop on AmazonA removable insert that brings a loud exhaust back under your state's limit.
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