It might be an easy fix, there's a rubber seal at the bottom of the window that catches runoff of water, over time it can start to curl up with being exposed to harsh weather, if you take the time to just give the window a clean and get all the moss etc off, and stick the rubber seal back down it might fix the issue, if not it might be an issue with the flashing.
It might be an easy fix, there's a rubber seal at the bottom of the window that catches runoff of water, over time it can start to curl up with being exposed to harsh weather, if you take the time to just give the window a clean and get all the moss etc off, and stick the rubber seal back down it might fix the issue, if not it might be an issue with the flashing.