Why traps alone never end an infestation
No. Traps alone rarely solve a real rodent infestation. Traps remove some of the rodents already inside, but without sealing entry points and removing attractants, new rodents keep coming and the problem returns.
Effective rodent control has two parts: reducing the current population and keeping new ones out. That usually means professional treatment plus "exclusion" — sealing the gaps around pipes, vents, and foundations that rodents travel through. Cleaning up food sources and clutter matters too.
A landlord who hands a tenant a few snap traps and calls it done is not addressing the cause of a building infestation. For an ongoing problem, the landlord is generally expected to do more than that. If traps keep failing because the real source is never handled, a free review can help you understand what a landlord is required to do.
This is general information about California tenant rights, not legal advice. Every situation is different.