While finding a bug here or there is just a fact of life in any home, tenants should be confident that their landlord has ensured they won’t share their rental unit with insects, rats, or any other kind of long-term infestation. If you find signs of rats, or any other unwanted guests taking up residence in your home, you should immediately notify your landlord or property manager. They are obligated by the warranty of habitability implied in every California residential rental agreement to respond within a reasonable time. 

Specifically, the law states, “(a) A dwelling shall be deemed untenantable for purposes of Section 1941 if it substantially lacks any of the following affirmative standard characteristics or is a residential unit described in Section 17920.3 or 17920.10 of the Health and Safety Code: (6) Building, grounds, and appurtenances at the time of the commencement of the lease or rental agreement, and all areas under control of the landlord, kept in every part clean, sanitary, and free from all accumulations of debris, filth, rubbish, garbage, rodents, and vermin.” (CA Civil Code § 1941.1.) 

Notably, this means the presence of rats or other pests makes the unit “untenantable,” in the words of the law, whenever the condition exists. The landlord can try some basic solutions without help, which might not be unreasonable given the sighting of only one rat or some rat droppings. But if a landlord puts out traps, sprays, or takes other measures and rats continue to appear, then the landlord needs to take further steps, which may involve calling in a professional to perform more advanced work like finding and sealing the points of entry or dealing with potential rodent nests on the property. Landlords or property managers may claim they are doing what they can to resolve the issue or address the root cause. Still, if they fail to resolve the situation or don’t address the root cause, they are not meeting their obligations under the law. 

If, ultimately, the rats haven’t left, and the landlord or property manager isn’t doing anything else to make them go, then it might be the case that while they haven’t evicted the rats, they have constructively evicted you.