Ran into coolant leak in Alero, not sure what it is

My friend was driving car around with it being low on coolant I suppose. She just got her oil changed and all the fluids should have been checked and filled thanks to Tireman! Anyways car starts to over heat tonight, she pulled over. I arrive, I filled the coolant tank with water. Notice coolant or liquid on the ground from when she pulled over and shut off her car. Did not get down to see what it was, however assume it was coolant. Driving back to my house now, as I am following her In my car. Arrive at Walgreen's and we go in get some antifreeze, and come out to notice a puddle. Kind of like water with some coolant, at least that is what it seemed like to me. So instead of wasting coolant I just had her grab some more water just so she can make it to my house. Made it to my house. Checked the house, did not seem like that. Could not tell where the leak was coming from due to me filling it with water and water and steam being inside the hood. I just notice when ever she stopped her car and like shut it off, it would pretty much leak badly. Like underneath the car dribbles/streams in couple spots. But when it was running I notice it only would drip a tiny bit.