Heat is a basic requirement
Yes. Working heat is a basic requirement for a livable rental in California, and a landlord who fails to provide or repair it may be breaking the law. State law lists heating facilities among the things a home must have to be considered fit to live in.
A broken furnace or heater — especially one left unrepaired after you report it — can make a unit legally uninhabitable. The problem is more serious in cold weather and for households with young children, older adults, or anyone with medical needs. Landlords generally must fix heating problems within a reasonable time after they are notified, and a total loss of heat should be treated as urgent.
Keep a written record: report the problem in a text or email, save your landlord's replies, and note how long you went without heat. That record often makes the difference later. If you have been left without heat, we can review what you may be owed at no cost.
This is general information about California tenant rights, not legal advice. Every situation is different.