The answer to 'HVAC system leaking water' is that there are several common causes, including a clogged condensate drain, a problem with the condensate pump, a refrigerant leak, or a cracked drain pan. Symptoms may include water pooling around the indoor unit, water dripping from vents or registers, and excess moisture in the home.
In many cases, the cause can be identified and resolved with some basic troubleshooting and DIY repairs. However, more complex issues like refrigerant leaks or damage to the HVAC system components should be handled by a professional HVAC technician. Attempting DIY repairs on these types of problems could be unsafe and may void the system's warranty.