Aftermarket Exhaust in Colorado
Replacing the exhaust system is legal in Colorado, but a muffler in good working order is required and cutouts or bypasses are prohibited. Modifications that make the exhaust louder than the originally installed muffler are prohibited.
Verified against primary sources · August 2026
What the law says
Replacing the exhaust system is legal in Colorado, but a muffler in good working order is required and cutouts or bypasses are prohibited. Modifications that make the exhaust louder than the originally installed muffler are prohibited. Removing the catalytic converter is prohibited by federal law (Clean Air Act § 203) regardless of state rules. Denver-metro counties require emissions inspection.
Specific Limits
- Cutouts
- prohibited
- Muffler required
- Yes
- Catalytic converter
- removal prohibited by federal law
Frequently Asked Questions
Are aftermarket exhaust legal in Colorado?
What are the exact aftermarket exhaust limits in Colorado?
Street-legal aftermarket exhaust picks
Gear that helps you mod without a ticket in Colorado.
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