Who Must Install CO Detectors in California? Complete Guide

Last verified: February 16, 2026

California carbon monoxide detector laws require approved alarms in dwelling units that contain a fuel-burning appliance, fireplace, or attached garage under Health and Safety Code Section 17926. The California carbon monoxide detector statute applies statewide to homes, rentals, and many hotel or short-term units, while CRC R315 sets placement, power, and interconnection rules for new construction and permit-driven work. In practice, owners should document installation near sleeping areas and on each level, keep service records for inspections and lease turnovers, and verify local amendments before final occupancy decisions.

Tenants must promptly report inoperable devices, and local building departments can enforce notice-and-cure steps before penalties. Coordinating annual testing routines with local fire guidance further strengthens statewide compliance.

This approach supports life-safety protections and legal defensibility for California property operators.

Key Takeaways

CO detector requirements for California
Applies to homes?	Yes
Applies to rentals?	Yes
Applies to hotels/STRs?	Yes

When Are CO Alarms Required?

Buildings with fuel-burning appliances
Buildings with attached garages
New construction
When building permits are required
CO alarms generally not required in an all-electric dwelling with no fireplace and a detached garage.
Compliance deadlines referenced in common guidance: July 1, 2011 (existing single-family dwellings) and January 1, 2013 (other existing dwelling units).

Where to Install CO Alarms

Outside each sleeping area in the immediate vicinity of bedrooms (e.g., hallway).
On each level/story of the dwelling unit, including basements.
In each bedroom containing (or opening to a bathroom containing) a fuel-burning appliance.

For detailed placement guidance beyond legal requirements, see where to place carbon monoxide detectors.

Device Requirements

Device must be approved/listed by the California Office of the State Fire Marshal (SFM).
CO alarms listed to ANSI/UL 2034; CO detectors listed to ANSI/UL 2075 (or successor standards).
In new construction/when required by code: hardwired to building power with battery backup; interconnected when multiple alarms are installed.
Battery-powered or plug-in with battery backup may be allowed in certain existing-dwelling retrofit scenarios where running wiring is not feasible (per code exceptions).
Combination smoke/CO alarms are permitted if listed/approved and provide distinct alarms for smoke vs CO.

Landlord and Tenant Responsibilities

Landlord: Install required CO devices and ensure they are operable at the time the tenant takes possession. May enter the unit (per Civil Code Section 1954) to install, repair, test, and maintain CO devices. Correct reported deficiencies.

Tenant: Notify the owner/agent if the tenant becomes aware of an inoperable or deficient CO device.

Some local building guidance addresses owner testing/maintenance duties for detectors in hotels/motels/lodging houses; verify applicability for your occupancy type and jurisdiction.

Enforcement

Enforced by: Local enforcement agency / building and fire code officials (varies by jurisdiction).

Enforcement typically occurs:

During building inspections for new construction and permitted alterations/repairs/additions (CRC R315 retrofit triggers).
After a local enforcement notice to correct (statute provides a notice-and-cure step before fines).

Enforcement and inspection practices vary by city/county; state statute provides the baseline requirement for existing dwellings with specified CO sources.

Penalties for Non-Compliance

Violation is an infraction punishable by a maximum fine of $200 per offense; the owner must generally receive a 30-day notice to correct before a fine is imposed.

Health & Safety Code Section 17926(c) (as commonly reproduced in city guidance and bill text).

Additional Notes

The state statute ties required devices to the presence of fossil-fuel burning appliances/fireplaces or an attached garage; code provisions govern technical installation details.
Local jurisdictions may adopt additional or stricter requirements.
Hotels and motels are explicitly covered under Health and Safety Code Section 17926(a)(2).

Official Sources & References

California Senate Bill 183 (Chapter 19, Statutes of 2010) - Carbon Monoxide Poisoning Prevention Act (adds H&S Code Sections 13260-13263 and 17926-17926.2) (state code, accessed 2026-02-16)
Chaptered bill text establishing statewide CO device requirements, responsibilities, and penalties.
City of Agoura Hills - Carbon Monoxide Detectors Q&A (citing H&S Code Sections 13262, 17926, 17926.1, 17926.2) (agency guidance, accessed 2026-02-16)
Government handout quoting statutory sections; includes UL standards, placement, landlord/tenant duties, and penalties.
Contra Costa County - Residential Smoke & Carbon Monoxide Alarms (based on 2022 CBC/CRC/CFC; CRC R315) (building code, accessed 2026-02-16)
Official local building inspection guidance summarizing 2022 California code requirements including power/interconnection and locations.
City of Milpitas - Carbon Monoxide (CO) Alarms/Detection handout (Aug 1, 2024) (agency guidance, accessed 2026-02-16)
Official city handout summarizing deadlines, triggers, and installation locations; links to SFM listing categories.

Disclaimer: This information is provided for general guidance and is not legal advice. Requirements may vary by city, county, and building type. Always verify current rules with local authorities and official sources.

Frequently Asked Questions

Are carbon monoxide detectors required in California homes and rentals?

Yes. California carbon monoxide detector requirements come from the Carbon Monoxide Poisoning Prevention Act, codified in Health and Safety Code Section 17926. Homes and rental units generally need alarms when the unit has a fuel-burning appliance, a fireplace, or an attached garage. Hotels and many short-term units are also covered by the same statutory framework. For new construction and permit-triggered work, the California carbon monoxide alarm code in CRC R315 adds technical rules on wiring, interconnection, and placement. Local jurisdictions may enforce stricter details, so use city or county guidance when planning compliance.

When is a California home usually exempt from the CO alarm requirement?

The statewide California CO detector law is risk-based, not occupancy-label based. Health and Safety Code Section 17926 ties the mandate to fuel-burning equipment, fireplaces, and attached garages. A fully electric home with no fireplace and only a detached garage is often outside the baseline trigger, but owners should still verify local building amendments before assuming exemption. Shared walls can also change risk analysis when neighboring units contain combustion appliances. Because local inspectors evaluate the whole dwelling context, many compliance teams install alarms even in borderline cases as a low-cost control.

Where should CO alarms be installed under California code?

California installation rules combine statute and building-code details. Health and Safety Code Section 17926 establishes coverage, while CRC R315 addresses where to install carbon monoxide detectors in California for code compliance. Standard placement is outside sleeping areas, with additional devices on each story and in bedrooms that contain fuel-burning appliances or adjacent bathroom equipment. Devices should be listed and approved by the State Fire Marshal, and combination smoke and CO units are acceptable when they meet listing standards. During remodels, inspectors often review both placement and power source in the same permit cycle.

Who handles maintenance of CO devices in California rentals?

California landlord carbon monoxide detector responsibilities start with installation and move-in operability. Under Health and Safety Code Section 17926, the owner must provide compliant devices in covered units. Tenants must notify the owner when an alarm becomes inoperable or deficient, and owners may enter for repair and testing under Civil Code Section 1954 notice rules. This split duty is important during turnover because missed notifications and undocumented repairs can create avoidable disputes. Property managers usually maintain service logs, battery checks, and work-order records to show continuous compliance.

What is the fine for missing a required CO alarm in California?

The California carbon monoxide detector statute sets a capped infraction model. Health and Safety Code Section 17926(c) allows up to a 200 dollar fine per offense, and the owner generally receives a written 30-day notice to cure before monetary penalties are imposed. While the direct fine is limited, the larger risk is operational: unresolved violations can delay inspections, complicate rental habitability disputes, and increase liability exposure after an incident. For that reason, compliance teams treat notice letters as high-priority corrective actions rather than waiting until a follow-up inspection cycle.

How do California rules differ from Texas carbon monoxide laws?

California has a clear statewide residential framework in Health and Safety Code Section 17926 plus code-level requirements in CRC R315. Texas does not currently impose a broad statewide home mandate and relies more heavily on local adoption and limited statewide sectors such as child-care operations. If you manage properties in both states, build separate compliance checklists instead of reusing one policy. For a side-by-side legal baseline, review Texas CO detector laws before finalizing procurement and inspection workflows.

Practical CO Detector Guides

Beyond legal requirements, these guides help you choose, install, and maintain CO alarms:

Where to place carbon monoxide detectors — room-by-room placement recommendations
CO detector beeping patterns — what different alarms mean
What to do if your detector goes off — emergency response checklist
CO resources and links — official agencies and safety information