On Fri, 22 Jan 2010 15:30:21 +0000 (UTC), HerHusband
wrote:

As far as I can tell, the water comes in somewhere around the door sill at
the bottom. I'm not positive, but I think the water runs down the sides of
the door against the weatherstripping then along the crack between the
metal sill and the the wood jambs. I've tried caulking these joints also,
which has helped, but the water is still getting in somewhere.

I say you are correct. Often door jambs are not prime/sealed at the
bottom, so water wicks up into the wood.

Caulking is best done when the door was/is installed, not as a fix
later on.

Exterior doors clean the sill, caulk along the jamb sides the width of
the threshold. Run two 1/2 inch beads of silly-caulk the length of the
threshold and set the door. Apply some foot pressure to seat (TH).

Caulk lines (top view)

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