Hi trailernovice,
Your welcome and glad the info helped. There are high odds, the windows are the leak source due to the puddling inside the living space, but there are many other ways too. If you find the windows are not the issue, then come back to us. There are ways to back into where other leaks can get into the living space.
Ideally you can test what you have now, before making drain cleaning/adjusting to create a baseline. Then later test again after the cleaning to see if you actually helped the problem. This adds support to you found the issue. If there is no change in drain flow before and after, then one needs to dig deeper until it all adds up.
Let us know how you make out.
John
