When it rains the drivers side floor board is wet. It is not leaking from the roof.

You don't way what type of vehicle you are driving. I will assume it has a sun or moon roof. Most of these have drain lines that run down inside the driver's side door pillar and exit through the floor pan onto the ground. Over time, these drain hoses dry out and shrink, often retracting into the drivers side kick panel. Then, all the rain water that drains from the sunroof will leak out onto the drivers side floor. If that is the case, you will need to remove the drivers side kick panel and repair or replace the drain line and reroute it through the exit hole in the floor pan.

Sounds like the sunroof rubber seal is leaking need to replace it before it rains more :-)

Check all rubber seals for wear or breaks (especially the sun roof) and around any glass. That may be why the sun roof doesn't work anyway...water gets in and rusts mechanism. I would start up top first, then work down.

On a dry day take a garden hose and shoot water in any area that could leak and check and see if there is water in any of those areas. Also check under the car to see if there are holes or cracks that could leak. A rust spot will sometimes leak as well.

Sounds like the door gasket or trunk gasket is not sealing.
You may have to take it to a body shop to find the problem.

There are drains for the sunroof that are located in the coners of the roof, these plug up and the water drains into car, you will need to remove the cover were the seatbelt is and see if the hose that connects to the drain fell off or if drain is plugged, open the roof all the way back and using a bottle filled with water , pour over the drains one at a time and see if it drains if not you will need to use a coat hanger and unplug them but i would still check for the hose off on the side that leaks water. good day.

2 possibilities. - Possible heater core leak - does it smell like anti freeze/coolant or windshield draining into cabin area.

There is a great possibilty that there is a leak on the Left Side of the Windshield. It is most likely in the area of the upper left side.
The reason for this conclusion is:
The rain water is coming in the Left Upper Side; and either coming down the "A" Pillar, or traveling underneath the trim on the inside roof and coming down the "B" Pillar.
The only other explanantion is a torn, worn, cracked or dislocated Weather Seal on one or both of the doors, allowing rain water to come in. Inspect very carefully these Weather Seals, especially on the top front portion of the rear door.
To help you locate these after a hard rain:
Take the trim panels off the "A: and "B" Pillars and the Roof Line above both Doors. Check for wetness underneath the trim. Or take these trim panels off, and place folded paper towels under the trim panels; reattach the trim panels and wait until it rains. Afterwhich, take these trim panel off and check the paper towels for wetness.
The Windshield Seal is easily inspected for cracks and tears.
Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!

do you have a sun roof, if so start there, because there are two hoses at the back corners of the roof pan that allow water to drain, if they leak, they will soak the rear floorboards, and if not that check the door jam seals.(note that if the plugs on the floor are missing that will be verry hard not to have wet carpet)........let me know?

Go to a car wash with a good flashlight, and watch where the water comes from.