The answer to 'why is my dryer vent mildew' is that a clogged or blocked dryer vent is the most common cause of mildew buildup. When the vent is obstructed, moisture and lint can accumulate, creating the perfect environment for mildew to grow. This is a common problem that can lead to reduced airflow, increased drying times, and even a fire hazard.
To address this issue, you'll want to inspect and clean your dryer vent on a regular basis. This includes removing any lint or debris that has built up inside the vent, and ensuring the vent is not blocked by items stored nearby or a bird's nest. If the mildew is severe or the vent is difficult to access, it's best to call a professional dryer vent cleaning service to handle the job properly.