Boulder, CO Noise Ordinances: Construction Hours (2026)
Construction hours in Boulder, CO, sometimes called construction noise rules or contractor work-hour ordinances, set when contractors can run power tools, hammers, and heavy equipment.
Key Facts
- Curfew hours
- 9 p.m. to 7 a.m.
- Applies to
- Power tools audible off-property, residential zone
- Requires
- Work under a required or issued building permit
- Daytime treatment
- Deemed industrial zone 7am-5pm (§5-9-3)
- Penalty
- Up to $2,650 fine, 90 days jail
Summary
Boulder bars audible construction power tools in a residential zone between 9 p.m. and 7 a.m. under Boulder Revised Code § 5-9-7(b): if the tool can be heard off the property where it is being used, and the work needs or has a building permit, running it during that overnight window is a violation regardless of decibel level.
5-9-7. Between the hours of 9:00 p.m. through 7:00 a.m., no person shall: ... (b)Construction in a Residential Zone: In a residential zone, use power tools which are audible off the property upon which they are being used as part of construction work for which a building permit has been issued or is required for the work.
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
Section 5-9-7(b) targets construction noise specifically, distinct from the general decibel table in § 5-9-3. It applies only in a residential zone, only to power tools used as part of permitted or permit-required construction work, and only if the sound is audible beyond the property line; hand tools or muffled equipment that cannot be heard off-site are not covered. ; amplified sound never qualifies for either deeming. m. There is no separate construction-noise variance; the general sound level variance in § 5-9-10 covers §§ 5-9-3 and 5-9-4 but is not extended by the code to § 5-9-7.
Violations & Fines
A § 5-9-7(b) violation carries the citywide general penalty, Boulder Revised Code § 5-2-4: up to $2,650 and up to ninety days in jail per violation, or both. Boulder's code enforcement and police respond to after-hours construction noise complaints, and a contractor can be cited even if the same work would have been lawful during the day.
Frequently Asked Questions
When can construction crews use power tools in a Boulder neighborhood?
Is quiet evening construction work allowed in Boulder?
Can a contractor get a variance from Boulder's construction noise curfew?
Sources & Official References
Other rules in Boulder
How Boulder compares: Cities with the Strictest Construction Hours·Compare Boulder to another location·View the Colorado noise ordinances overview
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Construction Hours in Nearby Cities
How other cities in Boulder County handle construction hours.