Why a clean home can still get mice
You can have mice even in a clean apartment, because rodents come in from outside or from other units through gaps in the building — seeking warmth and shelter — not just food scraps.
A tidy home helps, but it does not seal the holes rodents use or stop them from entering through the walls, from neighboring units, or from outdoors. Mice need only a tiny opening, and they are drawn to warmth and water as much as to food. In apartment buildings especially, a spotless unit can still get rodents when the building itself has entry points or an existing infestation.
That is why the responsibility usually falls on the landlord to seal and treat the building rather than on the individual tenant. If a landlord blames your housekeeping for a rodent problem that clearly comes from the building, that is worth questioning — and a free review can help you understand who is actually responsible.
This is general information about California tenant rights, not legal advice. Every situation is different.