If it is coolant it will be draining the system. A quick and easy way to check is to take off your radiator cap.
Before you do however, if it is a leak on the coolant system this will release the pressure, i.e. the air will have an easy way into the system; and the rest of the coolant will more than likely come out too. Not any more of a big deal as you'll have already lost most of it anyway! If it is coolant therefore, you will not be able to see any fluid in the radiator after taking the cap off.
My EP3 coolant was always up to the top of the radiator and I never topped it up myself, just the dealer on service etc, therefore if you do take the cap off and there is water near or at the top of the radiator then you definitely do not have a coolant leak. It must be something else.
As lottie said, it's not the washer bottle is it? My washer fluid is green because of the anti-freeze etc, but the bottle is on the left of the EP3 engine bay, as you look into the bonnet from the front.
As I see it, 5 fluids that could be what you describe:
Coolant - but not if your radiator is full
Washer - easy to tell, if you get no spray, hey presto
A/C - Is it cold when running?
Power steering fluid - Resi under the bonnet, easy to check
Brake fluid - Again resi under the bonnet, easy to check
If all the above are OK, it can only be condensation, right?!