I found the source of the leak. It is coming from an upstairs window. There are four, small factory made holes in the track that the screen in the upstairs window sits in. I poured water directly into the holes and was able to replicate the leak. On all of my other windows, these drainage holes sit out beyond the house so they drain to the outside. On this particular window, the window track is flush with the house. Would caulking the holes be a long- term solution to the problem? There is an opening at the end of the track to let built up water drain outside. Also, is this something that the siding installers should have been aware of? Is it their responsibility to come out and fix the problem? Thanks for your time and help.