Water leak under door on main floor into the basement!?!

Water leaking in through door on main floor down to basement.
My apologies if this isn't the right section to be posting this in.

I have a leak which is letting water come in under my door on the main floor of my house. I usually place a towel at the bottom of the door and it appears both ends of the towel are the most damp after a hard rain. On very windy and raining days it will leak so much that it penetrates down through the floor into my basement (Nothing major but the water leak is very apparent).

I found out this was happening because I noticed that small pools of water were building up inside the plastic covering containing the insulation for the interior walls, it just happens it was directly below where the water was coming in from under the door on the main level. The water had made its way through the floor and was dripping through my insulation eventually resting on the plastic covering.

I first thought this was entirely due to the water entering the house under the main floor door, but as a trail and error experiment I taped up one side on the the outside of the door between the vinyl siding and the left side of the door. The leak seemed to have stopped.

So now I'm in major panic mode because water is coming inside from what I think is under the door and now it seems to be entering the basement through the floor somewhere outside between the vinyl and left side of the door.

Is this fixable without getting some contractor in to take a look? Would this be considered structural?

I will add pictures tomorrow in my attempt to better explain what is happening and where the water is coming in.

Any advice or suggestions would be greatly appreciated!!

Thanks!

Pictures would help a lot.

This is not a structarul thing
what kind of deck do you have outside that door and is it at the same leval as your floor inside.
Is there any kind of roof over the door. Has the siding been changed, has the door been changed, how old is the roof, how old is the house.

Jamsill Guard Door & Window Sill Pan Flashing

All most no one ever takes the time to install a door correctly.

If someone pored a stoop or built a deck or stoop right up tight to the doors threshold water will always be getting in there. There needed to be a min. of a 4" step down, 7" is far better.
At least a dozen times a year we have to remove doors that this was done on and most often end up replaing the whole inside floor and sometimes even the rim joist, floor joist, in one case it had gone on for 10 years and even the foundtaion plate was rotted out.
If they did not wrap the house wrap around the roughed in framing, install a sill pan for the door to sit in, install 6" wide window and door tape around the opening before installing the door.
Once the door was sat in place and nailed, a piece of Z molding needed to be installed over the top brick moulding, and a piece of 3/4 X 4 Or 6" vinyl lumber needed to be pushed up againt the bottom of the threshold and be screwed into place with stainless steel or ceramic coated trim head screw to fully support the threshold. Try stepping on your threshold in the middle and see if it does not flex causing the two sides near the jams to move and crack the sealing area.
If there was a sill pan there it would not matter because the water would be forsed outside.
Once all that's done the J moulding can go on starting at the bottom, the two sides then the top piece. The top piece must have a tab cut and bent over so water will run past the seams on the sides.
If a siding job is done correctly there should never be a need for caulking. Caulking will crack at some point and leak.

If someone does take the time to remove the door have them take the time to remove the wooden brick moulding and replace it with vinyl so it will never rot.

http://http://s1092.photobucket.com/albums/i419/DIYintraining/

The door is cover by the overhanging roof, also there is at least 7 inches between the bottom of the door and my deck.

I appreciate the responses so far and I thought the pictures my help!

Here are some pictures to shed light on what i'm talking about! I appreciate the responses so far, Thanks!

I forgot! There is a roof over the door and the house is only 2 years old. 7 inches between the bottom of the door and the deck.

I would bet on it being a poor flashing job or a leaky roof.

I'm almost positive it not the roof, if it is the "flashing" would I be able to fix it or would I have to get someone in to repair it? If I had to get someone to come in and fix it who would I contact? I want to solve this problem before the wood starts to rot

Thanks!

Get up in the attic and check for wet insulation around the door area. Newer houses with vapour barier are sealed up pritty good, If the roof leaks it may take awhile to work its way thru to the drywall. It wood be easy for it to run down inside the wall. Doors and windows is the kind of place it shows up first.