If you can ask someone to pour water on the cowl where the fresh air enters then look underneath the dash or where you suspect under the driver side.
Water on driver side floor after rain.
The floorboard on my driver side is always flooded after a good rain.
If it is indeed a leak during rain you can test it with a garden hose.
The driver side drain tube runs down the inside of the left pillar.
I have seen several cars that customers said they only get wet when it rains turn out to be plugged a c drains.
My husband ran the water hose over the door but could not find the problem.
You need to remove the pillar trim and the left kick panel to get at it.
2004 ford mustang the driver s side rear floor is absolutely soaked after a heavy rain.
We do not feel any water around the roof liner or other carpeting just the well where a rear passenger riding on the driver s side would put their feet.
I bought this car used and have only had it about thre months.
I noticed today cleaning those drains fixed the problem as no more water on the floor even after 3 inches of rain in 24 hours.
Interior water leak onto drivers side floor board on 2011 gmc sierra slt 4x4.
Check the drain port of the a c too.
I had to clean these holes out on both the passenger side and the driver side just prior to this big rainstorm we have had in calif in fact b c water was getting in and accumulating on my poor truck s floor pan.
If the drain is plugged the drivers side will get wet from the water backing up in the heater case.
One person told us to check door drain holes and i did check two 2 longish slots not holes along the bottom edge of the door.
Wet carpet on driver s side rear floor when it rains.