Waukesha County, WI Noise Ordinances: Vehicle Noise (2026)
Key Facts
- Governing law
- Wis. Stat. 347.39 (mufflers)
- County vehicle-noise rule
- None; state law controls
- Prohibited
- Cutouts, bypass, amplifying exhaust mods
- Typical fine
- About $98–$124, 0 points
- Enforced by
- Sheriff and municipal police
Summary
Loud vehicles are governed by Wisconsin state law, not a county ordinance. Wis. Stat. 347.39 requires an adequate muffler that prevents excessive or unusual noise and bans exhaust modifications that amplify sound. County sheriff and municipal police enforce it on all roads.
No person shall operate on a highway any motor vehicle subject to registration unless such motor vehicle is equipped with an adequate muffler in constant operation and properly maintained to prevent any excessive or unusual noise or annoying smoke.
Full Breakdown
The Waukesha County Code has no vehicle-noise chapter; instead, Wisconsin's equipment statute applies statewide. Wis. Stat. 347.39(1) requires every registered motor vehicle to have an adequate muffler 'in constant operation and properly maintained to prevent any excessive or unusual noise.' Section 347.39(2) prohibits cutouts, bypasses and any exhaust modification that amplifies noise above the original muffler. This covers loud cars, motorcycles and modified exhausts on Waukesha County highways and municipal streets alike. Separately, unreasonably loud stereo or revving that provokes a disturbance can be cited as disorderly conduct under Wis. Stat. 947.01.
Violations & Fines
Loud/defective-muffler forfeitures run roughly $98–$124 with 0 demerit points under Wis. Stat. 347.39; disorderly conduct (947.01) is a Class B misdemeanor for disturbances.
Frequently Asked Questions
Are loud exhausts illegal in Waukesha County?
Does the county have its own vehicle-noise limit?
Sources & Official References
Other rules in Waukesha County
Compare Waukesha County to another location·View the Wisconsin noise ordinances overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.