Warning signs of mold inside your walls
Signs of mold behind walls include a musty smell, dark spots or discoloration bleeding through paint, bubbling or peeling paint and wallpaper, soft or bulging drywall, and a history of leaks in that spot.
Mold inside a wall cavity can grow unseen for a long time, fed by a slow plumbing leak or moisture coming from outside. The wall may feel damp to the touch, look stained, or show paint that keeps lifting no matter how often it is repainted. Sometimes the first clue is not the wall at all but your body — allergy-like symptoms that are noticeably worse at home.
Because cutting into a wall can release spores throughout the room, it is best not to open it yourself. Instead, note the signs, photograph them, and report the problem in writing so there is a record of when your landlord was told. If a landlord dismisses clear signs of mold behind the walls, a free review can help you understand your options.
This is general information about California tenant rights, not legal advice. Every situation is different.