The answer to 'why is my dehumidifier leaking water' is that the dehumidifier's drain system is likely clogged or malfunctioning, causing the collected water to overflow and leak out. Common causes include a blocked drain line, a full collection tank, or a problem with the dehumidifier's internal pump.
If the dehumidifier is leaking, first check the drain line to ensure it's not kinked or clogged with debris. You can also try emptying the collection tank more frequently. If the problem persists, the dehumidifier's internal components like the pump or drain pan may need to be cleaned or repaired by a professional HVAC technician.