Multnomah County, OR Noise from Specific Sources: Car Alarm Limits (2026)
Key Facts
- Daytime limit
- 60 dBA, 7 a.m.-10 p.m.
- Nighttime limit
- 50 dBA, 10 p.m.-7 a.m.
- Bona fide alarms
- Exempt under § 15.270(D)
- Coverage
- Unincorporated county only, not Portland
- Penalty
- Class A violation fine, per day
Summary
Unincorporated Multnomah County caps sound from sirens and alarms at 60 dBA daytime and 50 dBA nighttime under the county Sound Control Law, but exempts genuine alarm-system activations: a real car alarm triggered by a break-in attempt isn't itself a violation.
It shall be unlawful for any person to produce or permit to be produced, with a sound producing device, sound which: (A) When measured at or within the boundary of the property on which a noise sensitive unit which is not the source of the sound is located, or, within a noise sensitive unit which is not the source of the sound, exceeds: (1) Fifty dBA at any time between 10:00 p.m. and 7:00 a.m. the following day; or (2) Sixty dBA at any time between 7:00 a.m. and 10:00 p.m. the same day;
Full Breakdown
The county's Sound Control Law (Multnomah County Code §§ 15.265-15.274) lists sirens and bells among the regulated 'sound producing devices' a vehicle alarm falls under. Section 15.269(A) caps unlawful sound from such a device at 50 dBA between 10 p.m. and 7 a.m., and 60 dBA between 7 a.m. and 10 p.m., measured at or within a neighboring noise-sensitive property. Section 15.270(D) then carves out 'bona fide use of emergency warning devices and alarm systems authorized by this chapter,' so a factory alarm genuinely triggered by an intrusion attempt is exempt from the decibel caps. The law reaches only unincorporated county territory. Portland, Gresham, Troutdale, Fairview, and Wood Village each enforce their own city noise codes instead.
Violations & Fines
A citation carries a Class A violation fine, with each day the excessive noise continues a separate offense; the court may also order a sound producing device used in a repeat violation seized and destroyed under § 15.273.
Frequently Asked Questions
Can I be cited if my car alarm goes off during a break-in?
Does this rule apply if I live in Portland?
Sources & Official References
Other rules in Multnomah County
Compare Multnomah County to another location·View the Oregon noise from specific sources overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.