2005 Ford F-150 water leak

Water leaks on passenger side floor and panel area whenever there’s even a moderate amount of rain. Trouble finding the source of leak.

If you have recently replaced the bulbs in the third brake light or cargo light, I’d check there, common problem with Fords. Might need a new gasket.

You need to check the Drain line from the HVAC case. https://www.f150online.com/forums/articles-how-s/419190-04-05-ac-drain-vent-instalation.html

Another possibility is that the cowl vent area drains are plugged. Try spraying water into the owl vent with a hose. If water shows up inside, you know where to start looking.