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Water on the passenger floor board

What is causing this ?

water on the passenger floor board when the air conditioning is on for a 2003 Honda Civic EX with 65,000 miles

Can’t say I have an answer, but I have a similar problem that’s getting annoying. My driver’s side floor board gets soaked anytime it rains, but I can’t find anywhere that water may be leaking through a window or door. Is there a way to test? A guy at the dealership looked at me befuddled and said he had no idea…2000 Toyota Camry, 210,000 miles…still runs smoothly…

Your air conditioner drain hose is either clogged or kinked. This is an easy fix. It should take your mechanic 5 minutes if you can’t find it yourself.

your heater core could be leaking.

Usually the drain is under the car right in front of where the passenger puts their feet. Careful use of some compressed air or some string trimmer line can clear them. Over use of either can cause additional and expensive damage.

  1. If the water only shows up when you run the AC it is, as Jeremy said, it is the AC condensate drain…and it is easy fix for either you or your mechanic.
  2. If the water shows up anytime or when you run your heater and smells “bad” it is a leak in the heater core. This is NOT an easy fix on your car and will be several hundred bucks.
  3. If the water shows up after a rain it is PROBABLY a plugged cowl drain. These are located 1 on each side of the cowl (the slotted thing just in front of the windshield) and can get plugged with leaves and dirt. You may be able to stretch out a coathanger and poke it around to clear it, but the only “permanent” way is to remove the cowl and then clean out the leaves and dirt. This is sort-of a medium hard fix that you might be able to do yourself. Sometimes a mechanic can blow compressed air up from the bottom of the drain (if they can find it!) for a temporary fix, but eventually the leaves will wash back.

I own a 2002 Hyundai Elantra which has developed a mysterious leak allowing water to come into the front passenger side floor when it rains. Not all rain storms result in water inside which is another mystery. The gasket on the right front passenger door was replaced but the leaking continued. I have had to rip up the carpet from the floor due to severe mold situation.
What I do know is that:
The water is not coming from under the dash as that carpet and foam area are never wet. It is not coming up from under the car because driving in a rain storm does not result in a wet floor. It is not coming in the side window as the door panel is never wet.
Do you think it might be coming from a plugged cowl drain which you mentioned?
Also how does one remove the cowl to clean out dirt/leaves?
Is this a job that someone who is not a mechanic can do?
Thank you for your time and assistance.

I have a 1997 Toyota Camry. Water was collecting on the front PASSENGER floor after a rain. I opened my sunroof and found the front drainage holes (about 1/8" diameter) in the corners of the track sunroof track. They looked clear. I poured a bottle of water in track and watched the result. Sure enough, water started dripping from the right ride of the glove box on to the floor. I started tearing out the interior panels to trace the leak. What I found is that if I poured the bottle of water REALLY slow into the sunroof hole = no leaks. But if I pour it too fast the small 1/8" hole cannot keep up and the track overflows! THAT is where the leak comes from in my car! If water overflows the track, then it makes its way down the column trim, around the glove box and on to the floor.

So I need to help the 1/8" sunroof hole drain faster. I took some 18AWG TFFN electrical wire and jammed it into the hole to help clean it out. I then removed the black plastic mud flap behind my front tire and blew out all of the leaves and rotted debris that where behind that flap. It was packed with junk! I poured more into the 1/8" hole and it seemed to drain quicker.

I hope this information helps others.