The telltale signs of a bed bug problem
Signs of bed bugs include small itchy bites (often in a line or cluster), tiny reddish-brown blood spots on sheets, dark specks along mattress seams, shed skins, and small live bugs about the size of an apple seed.
Bed bugs hide near where people sleep — in mattress seams, box springs, headboards, and cracks in the bed frame — and come out at night to feed. Look for rusty or dark stains on bedding, tiny pale eggs, and shed shells; in heavy infestations there may be a musty odor. Bites alone are not proof, because people react very differently, but combined with these physical signs they point to an infestation.
Catching bed bugs early makes treatment easier and gives you a clearer record. If you are seeing several of these signs, photograph them and report the problem to your landlord in writing so there is proof of when it started.
This is general information about California tenant rights, not legal advice. Every situation is different.