Solution is a tight bottom sweep doorseal and a rain splashguard or dripcap on the bottom outer face of door like the following link the type i use unless a fancy appearing one is desired easy to diy on most doors.
Front door leaking.
However in some instances the top corner of the door is the true culprit.
Find out how to fix a leak above the front door.
Designers and builders are aware of the issue.
Nevertheless they continually struggle to prevent water infiltration through this fundamental building element.
First try using a silicone caulk around the outside of the door.
Leaking exterior doors are a common problem affecting building owners and tenants causing property damage and requiring expensive repairs.
The most common cause of this is that the flashing above the front door on the outside of your home is breaking down and that s why the water is getting in.
If the leak persists take the siding off of the front of the house right above the door and properly seal the door with new.