The answer to 'grout mildew' is that grout mildew is a common problem caused by excess moisture, poor ventilation, and lack of cleaning. Grout mildew appears as black, green, or pink discoloration between tiles and can spread quickly if left untreated. The solution often involves a combination of cleaning, sealing, and improving ventilation in the affected area.
For minor mildew, homeowners can try DIY cleaning with a mild bleach solution or specialized grout cleaner. However, for more extensive mildew growth or if the issue keeps recurring, it's best to call in a professional cleaning service to properly treat the root cause and prevent future mildew buildup.