Castle Rock, CO Noise Ordinances: Vehicle Noise (2026)
Key Facts
- Adopted code
- Colorado Model Traffic Code (Title 10)
- State muffler law
- CRS 42-4-225
- Standard
- Prevent excessive or unusual noise
- Cutouts/bypass
- Prohibited
- Enforced by
- Castle Rock Police
Summary
Castle Rock enforces vehicle noise through the adopted Colorado Model Traffic Code plus CRS 42-4-225: every vehicle must have an adequate muffler in constant operation to prevent excessive or unusual noise. Loud exhaust and revving are cited.
Every motor vehicle subject to registration and operated upon a highway shall at all times be equipped with an adequate muffler in constant operation and properly maintained to prevent any excessive or unusual noise.
Full Breakdown
Castle Rock has adopted the Colorado Model Traffic Code by reference (Municipal Code Title 10), so state vehicle-equipment standards apply on Town streets. Under Colorado Revised Statute 42-4-225, every motor vehicle must be equipped with an adequate muffler in constant operation and properly maintained to prevent excessive or unusual noise; cutouts, bypasses and amplifying devices are prohibited. Loud stereos in vehicles also fall under the general noise code (Chapter 9.16), which limits sound audible 100 feet away. Castle Rock Police enforce both on Town roadways; there is no separate Douglas County vehicle-noise rule inside town limits.
Violations & Fines
Muffler and exhaust-noise violations are traffic citations under the Model Traffic Code / CRS 42-4-225, carrying fines and points. Report through Police non-emergency 303-663-6100.
Frequently Asked Questions
Is a loud exhaust illegal in Castle Rock?
What about loud car stereos?
Sources & Official References
Other rules in Castle Rock
Compare Castle Rock to another location·View the Colorado noise ordinances overview
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