The answer to 'why is my bathroom moldy' is that bathrooms are prone to mold growth due to the warm, humid environment. Common causes include poor ventilation, leaks, and high moisture levels. Symptoms include visible mold, musty odors, and discoloration on surfaces.
To address bathroom mold, start by improving ventilation by running the exhaust fan or opening a window during and after showers. Fix any leaks in plumbing, around the tub/shower, or in the ceiling. Wipe down surfaces with a mold-killing cleaner, and consider using a dehumidifier to keep humidity levels low. If the mold problem persists or covers a large area, it's best to call in a professional mold remediation company to properly assess and treat the issue.