I have a 2005 Chevy Tahoe Z71 and the driver's side carpet gets wet without it even raining so it appears that something is coming up from underneath it.....has any else had this problem and how can I fix it???

Doors don't normally leak as they have seals all around the edge, and the glass, unless yours are missing . Do you have a sunroof in it? Drains block or the pipes come unattached.

https://www.mazda6club.com/threads/drivers-side-carpet-gets-wet-when-it-rains.189807/

Or you have a blocked drain in front of the windscreen.

Or you have a hole in the floor.

Or the AC Drain is blocked.

If its cold during your rainy weather and you need heat to warm the interior of your car. You might want to have your cooling system pressure checked. The heater core might have developed some corrosion which will eventually lead to leaks. If you have radiator coolant in your cooling system, touch the wet carpet then rub your fingers together. There should be a film left on your fingers. Hope this helps.

ther will probably be a wire loom connector under the carpet under your feet and if the water has been getting to it I would saf that it will be correded and rusted . Check the wiring from front to back and check all connections for rust and rot

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!

Check the heater core unit located underneath the dashboard on the passenger side of the vehicle. Even though your car's antifreeze is red, it may appear to be clear when there is only a small amount present. Was the liquid in the vehicle sticky and have any smell to it?

I think that I can help you. It sounds like your drain-tube is plugged up. Get in the passenger side, and pull the carpet back from under the glove box. Look for a black rubber pipe that goes from a black box, and pokes thru the firewall, on the passenger side. Remove the hose from the box, and have a container ready to catch water. If water comes out of the black box, your drain hose is plugged up. Clean out the clog, and you will be golden.

Have your ac evaporator deain cleaned out or checked. Without this working the ac water will collect there.

Is it possible the water is actually coming from the A/C evaporator case, whose DRAIN IS CLOGGED ? The water produced by the A/C then leaks out of the case, down under the carpeting, then depending how vehicle is parked, can flow to the rear floors and carpet. Hope this helps

sounds like the air conditioning drain for condensation is plugged