Mildew
Mildew typically appears as a powdery white or gray film on surfaces in damp areas — shower tiles, window sills, and around plumbing. It's usually surface-level and easy to clean.
Mold
Mold often appears fuzzy or slimy and ranges from green and black to brown or orange. It can grow on or inside building materials, sometimes causing structural damage.
When to Call a Professional
Persistent growth that returns after cleaning, growth on or behind drywall, or anything that has spread beyond a small area is best evaluated by a professional inspector.