Longmont's Noise from Specific Sources: The Rules That Matter

Every city handles noise from specific sources a little differently. In Longmont, Colorado, there are 2 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.

Car Alarm Limits

Longmont exempts car alarms from its noise ordinance. Section 10.20.100.D.5.i excuses warning or alarm devices that signal an unsafe situation or call for police from the 50 to 75 dB(A) limits and the 10 p.m. to 7 a.m. quiet hours that apply to every other fixed noise source in the city. Separately, Chapter 6.98's private alarm system rules, including registration and false-alarm fees, expressly exclude alarm devices affixed to motor vehicles.

Key details: Governing exemption: LMC § 10.20.100.D.5.i, alarm/warning devices. Vehicle alarms excluded from: LMC § 6.98.020 alarm system definition. Nighttime residential noise cap (non-exempt sources): 50 dB(A), 10 p.m.-7 a.m.. Building false-alarm fee chapter: Ch. 6.98, does not cover vehicles. Remaining recourse: civil nuisance injunction under § 10.20.110.

Because section 10.20.100.D.5.i exempts alarm and warning devices from the noise code, and section 6.98.020 excludes vehicle alarms from Chapter 6.98 altogether, Longmont police do not write noise or false-alarm citations against a car alarm owner for the alarm itself. There is no dB(A) threshold, no quiet-hours cutoff, and no per-incident fee that applies. The one exposure that remains is civil: under section 10.20.110 a chronically malfunctioning vehicle alarm could be treated as a public nuisance, letting the city attorney petition a court for an injunction, though this is rarely invoked for a single vehicle and is aimed at the underlying nuisance rather than a per-incident fine.

The rules around car alarm limits in Longmont lean permissive, but that does not mean anything goes.

Delivery Truck Noise

Longmont Municipal Code § 10.20.100(D)(2) bars truck or rail loading and unloading within 250 feet of a residential lot between 10 p.m. and 7 a.m., with a carve-out letting retail grocery stores load overnight; a separate rule bans refuse-truck loading between 7 p.m. and 7 a.m. within 500 feet of a residential zone.

Key details: Residential buffer: 250 feet. Restricted hours: 10 p.m.-7 a.m.. Grocery exception: retail grocery store loading exempt. Refuse trucks: banned 7 p.m.-7 a.m. within 500 ft. Enforcement: general-penalty citation + nuisance suit.

Because chapter 10.20 states no separate criminal fine for a loading-noise violation, the Title 1.12.010 general penalty controls: up to a $500 fine and up to 90 days. Section 10.20.110 also deems a violation of § 10.20.100 a public nuisance, letting the city attorney sue to enjoin a business or carrier that repeatedly loads or unloads in the restricted window.

The Bottom Line

Longmont's noise from specific sources rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Longmont is broadly strict or permissive.

This guide is based on Longmont's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.