Any idea where the leak is coming from?

From your description, you have a coolant leak. One of the quickest way to ruin an engine is to have insufficient coolant. If your radiator had no coolant (water), running it could do damage. The leak could be coming from any number of places, as it can travel a good distance from the source by the time it hits the ground. Someone needs to have eyes on it to find the source. Many times a pressure tester is used for this. You need a mechanic or a someone knowledgeable on auto repair to find and fix the leak and fill it with the proper coolant. Straight water does not work.

this is my first contribution, so I hope it's helpful.

Something is amiss with the diagnosis of what's leaking and or the type of fluid. Even worse, I'm worried that you may have done more harm than good.

If it is truly coolant, it will likely be a green or orange color. It has a very distinct smell especially if it's burning / boiling. Whatever is in the coolant reservoir (a small tank that holds the extra coolant) should not be water. As someone mentioned, water will eventually boil and your engine will overheat.

The coolant system is a pressurized (when hot) loop that really shouldn't have anything added or removed anywhere besides the reservoir. If you have poured water in the radiator, the water could possibly boil as the engine warms. If there isn't an air pocket in the lines from opening them, the water turning to steam could potentially make one. This is bad as it may result in the engine running hot or potentially overheating. So whether or not it is determined to be leaking coolant, I would suggest a full flush at this point.

My diagnosis would start with the vehicle's history and usage in reference to when you noticed the issue. Was the car sitting for a long time or did you drive it the day before? Do you know the last time the coolant was flushed? If the car has been sitting a long time, it could be darn near anything. If the car was recently driven, it could be windshield washer fluid, or maybe even a little bit of water that was caught in a frame pocket or piece of trim.

From the description of the liquid alone, I think it may be windshield washer fluid.