I noticed (with the last 2-3 days) a large water spot on my back patio. I live in the city and have a patio, no yard. The spot starts about 10 feet away from the house and is about 8 feet long and 1-3 feet wide. There's not enough water for it to even be considered a puddle, it's just damp to the touch. I have no idea where to begin figuring out the source. There is no water inside the house anywhere and it's not coming from anything on the patio. It's literally in the middle of the patio.
Does anyone have any information or experience with this sort of thing? I'm a new homeowner and am slightly paranoid about things going wrong in my house.
Should I even be worried?