Small surface mold on a shower tile or windowsill (usually under 10 square feet) can often be handled with regular cleaning products. But if you see mold spreading across a larger area, smell a persistent musty odor without visible growth, or have had recent water damage or flooding, it's likely gone beyond a DIY fix and warrants a professional inspection.

Mold needs moisture to grow, so it typically shows up wherever there's excess humidity, leaks, or poor ventilation. Think bathrooms, basements, around windows, under sinks, or near roof leaks. Even a small, unnoticed leak can lead to significant mold growth within 24-48 hours if left unaddressed.

Mold exposure affects people differently. Some people experience allergy-like symptoms such as sneezing, coughing, or skin irritation, while those with asthma, respiratory conditions, or weakened immune systems may have more serious reactions. Regardless of symptoms, mold should be removed since it can also damage building materials over time.

A professional job typically starts with an inspection to identify the source of moisture and extent of growth, followed by containment (to prevent spores from spreading to other areas), removal of affected materials, HEPA vacuuming and air filtration, and treatment of surfaces. Just as important is fixing the underlying moisture issue so the mold doesn't come back.

Costs depend on the size of the affected area and severity, ranging from a few hundred dollars for small, contained jobs to several thousand for extensive contamination requiring structural repairs. As long as the moisture source is properly fixed and the area is dried out completely, mold shouldn't return to that spot.