Very important, is the water leak green like the engine coolant, this is a leaking heater core (very serious problem) or if it is it clear, your problem is the drain for the air conditioner drain is blocked (minor problem) there is a hose low on your firewall that is supposed to drain you A/C but yours is blocked, commonly by a wasp nest or something similar and is easily unblocked with no threat to your engine

Check for blocked up drains at the base of the windscreen..