The answer to 'why is my thermostat leaking water' is that the thermostat's humidity sensor or control mechanism is likely malfunctioning, causing it to detect excessive moisture and leak water. This can happen if the thermostat is installed in a high-humidity area, or if there is a problem with the HVAC system itself.
Some common causes of a leaking thermostat include a faulty humidity sensor, a clogged condensate drain line, or issues with the HVAC system's refrigerant levels or airflow. Depending on the specific issue, the solution may involve recalibrating the thermostat, clearing the drain line, or having a professional HVAC technician inspect and repair the system.