Water under driver's side floor mat

It’s a '93 Cutlass Ciera. I’ve noticed water under my driver’s side floor mat for the last couple weeks. I thought it was originally just water from wet boots and would dry out eventually, but it hasn’t. I read through a couple other threads on here re water under floor mats and some suggestions were leaking door seals, windshield seals, clogged A/C drain, or water coming up from the road. We have had a pretty wet past couple weeks here in PA and I know the underside of my car is not in the best shape. I looked right underneath the foot well and didn’t see any obvious places where water could get in. I’m also not usually running the A/C (although I have used the defroster a bit).

Someone in another thread suggested using a water hose on the car to see if there are any obvious water leaks. Maybe I should do that next.

Thanks in advance!

If you’re using the defroster, than you are using the ac. The ac comes on to dry out the air. I would clean out the drain line to the ac box. It’s a rubber line that passes through the fire wall. You can blow it out with compressed air or a pipe cleaner. Does it smell sweet and is it oily? If not than it’s just water. If this doesn’t fix it, than I would start checking seals.

A couple other ideas. Look at the underside of the door, make sure the openings there aren’t clogged with rust/debris. Use a screwdriver or something to probe, make sure they are all open. Water will always get into the door b/c the seal to the window is never 100% water tight, since the window has to go up and down. The door is designed so water that gets in drains right back out the bottom of the door, and too the outside by the way the door threshold is shaped. But that only works if the holes in the bottom of the door are open.

Also, do you see those vents just under the windshield? On the outside of the car? They allow fresh air into to the HVAC system, but rain will get in there too. On my early 70’s Ford truck there’s a sort of plastic bucket gadget near where your feet go designed to separate the water (which is heavier so it accumulates at the bottom of the bucket) from the fresh air. The drain hole in the bottom of that bucket can get clogged. 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. 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. Not sure if this technique is used with cars of your vintage, but there has to be some way to drain water that gets into those vents back out of the car, and the path could be clogged.

It’s a good idea to occasionally use a shop vac to vacuum leaves and other debris from those fresh air vents under the windshield, can help prevent the drain holes lower down in the system from clogging. I do this every 3 months.