When a broken sprinkler system is a violation
If your building is required to have fire sprinklers, keeping that system working is generally the landlord's responsibility, and a disabled or broken system can be a serious safety violation.
Many larger apartment buildings are required to have working sprinkler systems, which are designed to slow or stop a fire and give people time to escape. A system that has been shut off, damaged, or left without maintenance may not activate when it is needed most.
You may notice signs of trouble such as sprinkler heads that are painted over, blocked by stored items, leaking, or clearly damaged, or notices that the system has been turned off. These are worth reporting.
Report the problem to your landlord in writing, and note that it is a fire-safety concern. Your local fire department can inspect the system and order repairs if the building requires one. Because a non-working sprinkler system can put an entire building at risk, it should not be ignored. A free, confidential review can explain your rights if the landlord will not act.
This is general information about California tenant rights, not legal advice. Every situation is different.