The answer to 'carpet mildew' is that it is a common problem caused by excess moisture, poor ventilation, or water damage. Symptoms include a musty odor, visible mold growth, and discoloration of the carpet fibers. Solutions depend on the severity of the issue, but may include deep cleaning, treating the affected area with a mildew-killing solution, or in severe cases, replacing the carpet.
If the mildew is limited to a small, isolated area, you may be able to address it yourself. However, for widespread or persistent mildew, it's best to call in a professional cleaning service. They have the expertise and equipment to properly identify and resolve the root cause, preventing the problem from recurring.