Gas safety and the landlord’s duty
Treat a gas smell as an emergency. Leave the area right away, avoid flames, light switches, and anything that could spark, and call your gas utility or 911 from outside — then notify your landlord. Gas lines and appliances are the landlord's responsibility to maintain and repair.
A gas leak is a serious safety hazard, so your safety comes first. Do not try to find the source yourself or turn things on and off. Once you are safely away and the utility has been contacted, report the problem to your landlord, since maintaining gas plumbing and appliances in safe working order is their duty under California habitability law.
A landlord who ignores a known gas problem is putting tenants at real risk. Keep a record of when you reported it and what the landlord did. If your landlord ignores a gas safety problem, a free review can help you understand your options.
This is general information about California tenant rights, not legal advice. Every situation is different.