Ok so i already looked underneath the and there is no visible rust. The carpet floor, floor only was wet. I think the water is comming from the bottom not the top because there is no streak marks.

How do i go about finding the leak spot and fixing it?

 

What kind of roof on car? Hard top or TTop? Pass side carpet? Dr side? front DR or Pass? rear dr or pass? hatch carpet?
If the top of the carpet is wet but the bottom isnt your leak is from the top.
It sounds to me like your deck lid to glass seal is bad (trunk water) and your body to hatch hinges are leaking.
TTops maaaybe leaking also if you have them.
A GM service manual from HELM INC is veeery helpful and worth the money.

 

Are you sure the passenger side floor wasn't coolant? If the heater core goes the passenger side foot area will get wet with coolant.

 

Look at sidemarker lights, they will allow water in surprisingly.

 

That wouldn't get water on the hatch carpet tho. It would drain out of the holes in the spare tire well (pass side) or the locking compartment quarter panel hole (dr side)

 

Check if the wheel wells are rusted.

For the passenger side floor, most likely somewhere in the firewall. Maybe somewhere by around the heater box.