Maricopa County, AZ Noise Ordinances: Vehicle Noise (2026)
Key Facts
- Governing law
- Maricopa County Ordinance P-23
- Muffler required
- Working muffler required at all times
- Amplification devices
- Cut-outs, bypass devices banned outright
- Max fine
- $750 for third or later offense
- Scope
- Unincorporated Maricopa County only
Summary
Maricopa County bans motor vehicles without a working muffler and prohibits cut-out, bypass, or muffler-elimination devices that amplify engine or exhaust noise, enforced in unincorporated areas under Ordinance P-23.
It is unlawful for any person to operate any motor vehicle that is not equipped with a muffler in good working order and in constant operation to prevent excessive noise. It is unlawful for any person to operate a motor vehicle equipped with a cut-out, by-pass, or similar muffler elimination unit, or to operate a motor vehicle with devices that amplify motor noise or motor vehicle exhaust noise.
Full Breakdown
Under unincorporated Maricopa County's Noise Ordinance P-23, every motor vehicle must run a muffler in good working order at all times; cut-out, bypass, or similar muffler-elimination systems and any device that amplifies motor or exhaust noise are banned outright. The ordinance also bars sounding a horn for anything but its lawful purpose and causing tire squeal from rapid acceleration or excessive speed. Excessive engine revving while stationary is allowed only during repair or testing between 7 a.m. and 8 p.m., and only if the muffler and anti-amplification equipment stay intact. First-offense fines top out at $300, rising to $750 for a third violation.
Violations & Fines
Misdemeanor citation through Maricopa County Justice Court: up to $300 for a first offense, $500 for a second, and $750 for a third or later violation; each day it continues counts as a separate offense.
Frequently Asked Questions
Can I remove my truck's muffler in unincorporated Maricopa County?
Does this noise rule apply inside Phoenix or Mesa?
Is revving my engine while parked ever legal?
Sources & Official References
Other rules in Maricopa County
Compare Maricopa County to another location·View the Arizona noise ordinances overview
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