Boulder, CO Noise Ordinances: Quiet Hours (2026)
Quiet hours in Boulder, CO, also called the noise ordinance, nighttime noise rules, or residential quiet time, define the hours during which excessive noise is prohibited.
Key Facts
- Curfew hours
- 11 p.m. to 7 a.m.
- Where it applies
- Public property in a residential district
- Standard
- Louder than normal conversational speech
- Related home rule
- §5-9-5 requires a prior warning first
- Penalty
- Up to $2,650 fine, 90 days jail
Summary
Boulder's nighttime noise curfew runs 11 p.m. to 7 a.m. Under Boulder Revised Code § 5-9-6(b), anyone on public property in a residential district during those hours is barred from yelling, screaming, shouting, cheering, or singing louder than normal conversational speech. A related law, § 5-9-5, lets residents get an official warning issued against a repeat noisy neighbor at any hour.
(b)Unreasonable Unamplified Noise:(1)Between the hours of 11 p.m. and 7 a.m., while on public property within a residential district, no person shall yell, scream, shout, cheer, sing, or otherwise make noise with the human voice louder than that which is reasonably necessary for normal conversational speech.(2)It shall be an affirmative defense to a charge of violating this subsection that the noise was reasonably necessary to gain assistance to prevent a crime, catch a criminal, warn of fire or other danger, or to seek assistance for a health problem or injury or for assistance in dealing with an accident.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 167 Update 3).
Full Breakdown
m. It does not require a decibel meter; the standard is whether the volume exceeds what is reasonably necessary for normal conversational speech, judged against an objective reasonable-person standard. The only affirmative defenses are noise made to summon help, such as stopping a crime, warning of fire, or getting medical assistance. This is separate from § 5-9-5, Disrupting Quiet Enjoyment of Home, which lets a person cited for a course of loud conduct that materially interferes with someone's home life be prosecuted at any hour, but only after that person has already received a warning for the same or similar conduct within the past ninety days; a warning letter mailed to 'residents' of a unit can also satisfy the prior-warning requirement for every occupant.
m. Together the three sections give Boulder Police three distinct nighttime tools: a measured decibel cap, a human-voice conduct rule for public space, and a warning-based home-disruption charge.
Violations & Fines
A § 5-9-6(b) violation is a municipal offense under the citywide general penalty, Boulder Revised Code § 5-2-4: a fine of up to $2,650 and up to ninety days in jail per violation, or both. Boulder Police respond to nighttime noise complaints and may issue a citation on the spot for public-property shouting or singing that exceeds normal conversational volume during curfew hours.
Frequently Asked Questions
What are Boulder's quiet hours?
Can I be cited for a loud house party in Boulder?
Does the quiet-hours law apply on private property?
Sources & Official References
Other rules in Boulder
How Boulder compares: Cities with the Strictest Noise Ordinances·Compare Boulder to another location·View the Colorado noise ordinances overview
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Quiet Hours in Nearby Cities
How other cities in Boulder County handle quiet hours.