My 89 civic has been getting a rain puddle comming through the carpet in the rear right foot well. The leak is towards the left of the right footwell and the carpet near the door is dry as is the rear left foot well. The inside door panels and roof are dry and there are no other visible inside wet spots. It seems that the water is rising up from the floor. I can't seem to figure out where the water (a significant amount) is comming from. Any suggestions on what I can do?

 

Pull the carpet back and see if there is a rust hole, or one of the plugs has come out. Also check your door seal as it could cause an issues possibly or the sun roof drain if you have one.