Smoke & Carbon Monoxide Detector Installation:
Code & Safety Guide
Complete guide to smoke and carbon monoxide detector installation in Los Angeles. California code requirements.
Published: June 2026 · Updated: June 2026
Safety Guide
Smoke and CO Detector Requirements in Los Angeles
California has strict smoke and carbon monoxide detector requirements.
Code Requirements
California Smoke & CO Detector Requirements
- Smoke Alarms: Every Bedroom
Inside every bedroom and outside each sleeping area. - Smoke Alarms: Every Level
At least one on every level including basements. - CO Alarms: Every Unit
Required in every dwelling with fuel-burning appliance or attached garage. - Interconnection Required
All smoke alarms must be interconnected since 2014. - Hardwired for New Construction
Requires hardwired with 10-year sealed battery backup. - Home Sales Trigger Requirements
Current code compliance required at sale.
Installation Costs
Installation Cost Ranges
| Item | Typical Range |
|---|---|
| Hardwired Smoke Alarm | $150 – $300 per unit |
| Hardwired CO Alarm | $150 – $350 per unit |
| Hardwired Combo Smoke/CO | $175 – $350 per unit |
| 10-Year Sealed Battery (installed) | $100 – $200 per unit |
Costs vary by attic access and wiring.
Related
Related Services & Resources
Questions
Frequently Asked Questions About Smoke & CO Detectors
Where should smoke detectors be placed in my LA home? ▾
California code requires smoke alarms inside every bedroom, outside each separate sleeping area (like a hallway), and on every level of the home including basements. In multi-story homes, you need at least one smoke alarm on each floor. All alarms must be interconnected so that when one sounds, they all sound.
How often should I replace smoke and CO detectors? ▾
Smoke alarms should be replaced every 10 years from the date of manufacture (not the purchase date). Carbon monoxide alarms have a lifespan of 5 to 7 years. Check the back of each detector for the manufacture date and set a reminder to replace them before they expire. Interconnected hardwired units with sealed 10-year batteries simplify maintenance.
Do I need hardwired or battery-operated smoke detectors? ▾
California law requires hardwired smoke alarms with battery backup for all new construction and major renovations. For existing homes, 10-year sealed battery alarms with wireless interconnection are a code-compliant alternative that avoids running new wires. Both options meet California requirements when properly installed and interconnected.
Ready to Get Started?
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Written by Amy
California C-10 Licensed Electrician · EVITP Certified · 15+ Years Experience
Amy is the founder and lead electrician at AMY Electric, serving Greater Los Angeles since 2012. He holds a C-10 Electrical Contractor License (#981578) and EVITP Certification (#4051604). All recommendations are based on first-hand experience from over 200 completed projects.