So my 2007 2.2 Civic has had this water in the boot problem for a few weeks now. Simply have not got around to getting it seen to by a garage and I actually want to address the problem myself. The first time I noticed it, the carpet in the under compartment was soaked, and when I got around to pulling it out (after removing the plastic trim) there was a good litre or two of water swimming around in the metal boot well. I had to pull some carpet and trim out and dry it out and replace some of the padding. I was initially convinced the leak was coming through the lights as sometimes there is a small drop of water coming through the nearside hatch/cover that covers the lights access, and there are a few spots of condensation within the lights themselves. However, after a couple of weeks of dreadful rain and washing my car once or twice in-between, there was no more water coming through that light cover. The seals from what I can see of them, look good also. With the tailgate right up, I placed my hand into the hatch opening and reached upward, and felt something and gave it a wiggle, and instantly felt water. It is a small yellow plastic lug and when moved it allowed some water drops in around it. I sealed around this with tiger seal (with great difficulty reaching in). However, this does not explain the large pool that keeps amassing in the boot well. Each time this happens, I have painstakingly inspected the boot hatch and the lights and the rubber and trim and there are no leaks and no evidence of water dripping or coming from above. I have sat in the car with a torch for a long time while outside torrential rain hammers down, and nothing leaks in. I have placed paper tower around the lights, stuffed into the hatches, and they have remained totally dry. The plexiglass window is also totally dry, no sign of any leaks. The water seems to be appearing within the bottom of the well, on the nearside, almost as if by some kind of Merlin wizardry. I always move the hinged carpet lid back up into place and it shows no sign of wetness or drips from above. It is worth noting the vertical carpet trim over the wheel arch on the nearside was also soaked, and pulling it out a little and placing my hand up behind it I could feel it was soaked up and behind and I had to pull out the padding from behind here also. All the rubber bungs in the boot well and are in place and sealed, and there is no obvious sign of wetness seeping in from anywhere, no trail of water, no drip line, no splashes. It is at the moment a complete mystery. I wonder if water is coming through the wheel arch somehow or a welded seam under the wheel arch carpet trim? The ingress only seems to occur after driving the car in wet conditions, even a short distance. While sat, it seems fine and nothing comes in or accumulates. Has anyone else had this same issue or could maybe shed any light on where this water is coming from?