Boulder, CO Building Safety: Carbon Monoxide Detectors (2026)
Key Facts
- Trigger
- Fuel-fired heater, appliance, fireplace, or attached garage
- Placement
- Within 15 feet of each sleeping area entrance
- Existing rental deadline
- Alarm required at first tenant change after July 1, 2009
- New construction
- Alarms required in all newly built or renovated rental units
- Multi-family exception
- Up to 25 feet from source if centrally monitored
- Inspection frequency
- Annual operability check; battery replaced as needed
- Tampering ban
- Detectors may not be disarmed or have batteries removed
Summary
Boulder's Property Maintenance Code requires carbon monoxide alarms in every existing dwelling and rental with a fuel-fired heater, appliance, fireplace, or attached garage. Section 705.4 sets a 15-foot placement rule near each sleeping area, a 2009 deadline for existing rentals, and an owner duty to replace failed alarms. Rental inspectors verify compliance before every license issuance or renewal.
705.4 Carbon Monoxide Alarms. Carbon monoxide alarms shall be installed in existing dwellings and rented single- and multi-family dwellings that have fuel fired heaters, appliances, or fireplaces, or attached garages based on the following: 1.Alarms must be installed within 15' of the entrance to each sleeping area and must be wired to AC power, connected to an electrical panel, plugged into an electrical outlet without a switch or, if battery operated, attached to the wall or ceiling per the manufacturer's installation instructions and in accordance with Chapter 10-8, Section 915, "Fire Code," B.R.C. 1981...2.Alarms must be installed in existing rental dwellings upon change of tenant occupancy after July 1, 2009.3.Alarms must be installed in all newly constructed or renovated single-family and multi-family rental units...5.Rental owners are responsible for replacing nonfunctioning carbon monoxide alarms upon written request of the tenant or when the unit is being vacated and re-rented.6.Carbon monoxide detectors shall not be disarmed, removed or have the batteries removed to make them inoperable.
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
S. 4 applies to existing dwellings and to rented single- and multi-family units that have a fuel-fired heater, appliance, or fireplace, or an attached garage. Each alarm must be installed within 15 feet of the entrance to every sleeping area, and it must be wired to AC power, connected to an electrical panel, plugged into a switchless outlet, or, if battery-operated, mounted on the wall or ceiling per the manufacturer's instructions and Fire Code Section 915. Existing rental dwellings needed an alarm the first time the tenant changed after July 1, 2009, and every newly constructed or renovated single-family or multi-family rental must have one from the start.
A multi-family building used for rental can space an alarm up to 25 feet from a fuel-fired source only if the building runs a centralized alarm system, or another mechanism, that lets a responsible person hear the alarm at all times, meaning a commercially monitored system. 5 requires an annual operability check, with battery-backed units checked for good working order and batteries replaced as needed. 4(6). The rule connects directly to Boulder's rental licensing chapter: under Sections 10-3-6(a)(2) and 10-3-7(a)(2), the licensed rental housing inspector must certify the condition and location of every required smoke and carbon monoxide alarm before the city issues or renews a rental license.
Violations & Fines
Boulder does not publish a flat carbon monoxide fine schedule inside Section 705, but the rule is enforced through the rental licensing system: a licensed inspector must certify every alarm's condition and location under Sections 10-3-6(a)(2) and 10-3-7(a)(2) before the city manager issues or renews a rental license, so a missing or nonfunctioning alarm can hold up licensing. Disarming, removing, or de-batterying a detector under Section 705.4(6) is a separate code violation.
Frequently Asked Questions
Does every Boulder rental need a carbon monoxide alarm?
Where must the alarm be placed?
Who has to replace a dead alarm?
Can a tenant remove the alarm?
Sources & Official References
Other rules in Boulder
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Carbon Monoxide Detectors in Nearby Cities
How other cities in Boulder County handle carbon monoxide detectors.