Excessive coolant/water

The only way to find out if it has a leak is to have it pressure tested. This will determine if it is holding up the pressure. If it can't hold the pressure then it has a leak somewhere that is not easily seen. Logic tells you that if its loosing coolant then it has to go somewhere. Sometimes the leaks are coming from a worn out cap. When the pressure inside increase, the water comes out slowly enough for you not to notice anything. Also check the small hoses that go to the throttle body. and the heater hoses. If the car has a tendency to run a little hot, don't take that for granted, because that could be the reason why you are loosing coolant. The sooner you find out the problem the better, because you know this is just the first stage, and if left alone will get worse over time untill it becaomes a major problem. Glad you posted it.