When rodents are inside the structure
Yes, usually. Rodents living in the walls, ceilings, or crawl spaces of a building are generally the landlord's responsibility, because the infestation is inside the structure the landlord must maintain.
Scratching or scurrying sounds in the walls and ceiling at night are a classic sign of rodents nesting inside the building. Getting them out often requires professional treatment and sealing the entry points they use to move through the structure — work that falls to the landlord, not the tenant. It is not reasonable to expect a tenant to open walls or access crawl spaces to solve this.
Left alone, rodents in the structure keep multiplying and can chew wiring or leave droppings that affect the unit below. If you hear rodents in the walls and your landlord will not act, that is worth taking seriously — a free review can help you understand what the landlord should be doing.
This is general information about California tenant rights, not legal advice. Every situation is different.