Water on floor, carpet is soaked!

I have a 2005 Honda Pilot that has developed a bad leak. The floor on the driver and passenger side gets wet. The driver side is usually damp and the passenger side floor is soaked, squishy, like a wet sponge. I have taken apart the dash and cleaned out the AC ducts and replaced the filter. I found some small leaves, not a lot. No help, still wet. I took off the plastic cowl under the windshield, it was really clean there, no leaves or junk and no signs of water there at all. Still gets wet. The area that is wet is right along the rocker panel near the plastic cover for the door sill, on both driver and passenger sides of the car. The carpet is only wet in the front seat “foot wells”, not the back seat areas. I looked at the seals, they seem to be working fine and cannot find anyplace water could be getting in. Either from the top side or underneath. I thought it was drying out then we got lots of rain the other day and the passenger side is saturated and the driver side is damp again. Not sure if it was from driving or sitting in teh driveway/parking lot at work. I looked all over the Interweb, lots of guys trying to seal body seams, taking off the fenders, really going nuts! It does not seem like it helps either!

It appears to be a common problem but I cannot find any solutions. Any ideas? Help quickly, the car is starting to smell!

Does the vehicle have a sun/moon roof?


+1 to Tester’s question.
Most sun/moon roofs run off into a surrounding “moat” that drains through a channel enclosed in the “A” pillars. These can get clogged and divert the water into the passenger cabin.

Also verify that water that gets into the cowling under the windshield has a clear path to drain out to the ground. Run some hose water there and see if it comes out underneath the car freely, and isn’t diverting inside the car. There’s a gadget in that path, often difficult to locate, that allows vent air to flow through and into the car, but divert rain water that gets in, back out. If that gadget gets obstructed with debris this symptom can result.

If all else fails just put a lawn sprinkler on top of the car, turn it on and wait until you can see where the water is getting in.

The car does not have a sun roof. I will try the garden hose trick. Looking into the cowl area with the plastic cover off, there was no debris int he cowl itself. In the AC/Heater area by the filter, there were some small leaves in there that I cleaned out. Where are these vent thingy parts that will need to be cleaned?? What can I search for to clean out the debris?

I had a similar leak in my 2000 Blazer, there was a split in the seam between the firewall and the side. I spotted the leak with a flashlight. Any water will reflect the light and will be much easier to spot.

Good luck,

Ed B.

I now have the car in the driveway with the hood open and a garden hose running water full blast down the windshield and into the cowl (alternating locations every 10 minutes or so). I have sopped up as much water from the carpet and underlayment as possible and have yet to see new water come into the compartment, even with the carpet pulled up. It is really cold outside to be messing with this thing (43deg!). My fingers are frozen and I still have not found the smoking gun.

Please keep the ideas coming!

I just took some photos and think I have found new water in the floor pan area…

The question is, how do I track it back to the leak? Could it be the windshield seal? Sorry guys, I cannot get the pics off my phone…

I dunno, is the floor itself sealed? Any grommets missing underneath the carpet? You might be to the point that you need to pull the carpet out so that you can better trace where the water is actually coming from. If its coming from behind the dash you should be able to see water tracks from above but awfully hard with the carpet still on the floor. You also need to get that carpet dried out pronto so that mold doesn’t form, so I’d pull the carpet and have a closer look for a while.

When I first got my G6, I discovered water in the spare tire area. Couldn’t figure it out so pulled the tail lights and sealed some seams that didn’t look right with seam sealer. The problem still persisted so I pulled the tail lights again and got the hose back on it and low and behold a grommet was out of place behind the bumper. When I had the hitch put on, they disturbed it and didn’t put it back again. It just took a lot of looking and the hose made it evident.

Take the carpet out, it will never dry in the car anyway. Then you have a better chance of finding the source.

Check Along The Bottoms Of The Front Door Interior Trim Panels.

Cars have a Water Deflectors (Sheet or molded plastic) Behind The Trim panel and attached to the steel door shell. Sometimes butyl or another adhesive is used to seal the deflector to the door shell and it fails. Properly attached deflectors channel water through the door and prevent it from entering the vehicle.

Flood the outside of the doors (entire door and window, top to bottom), with water and see if you detect any drips form the bottom edge of the trim panels. If leaks are detected then removing the trim panels and inspecting the deflector will reveal an area of failure (Usually bottom edge). Reseal it with butyl strips available from an auto glass installer.


I had a similar problem w/my Ford truck. I used all the ideas above to find where the leaks into the cab were coming from. Probably the most effective method was a helper spraying water on the truck while I layed underneath seeing if and where the water comes out the intended drain path. On my truck there’s a gadget on each side of the cab that collects rain water hitting the windshield and hood and drains it to the ground, and for the door windows, the underside of the doors have drain holes. All of those outlet ports were blocked or partially blocked with twigs and leaves. Its much easier to see them from underneath than above. Cleaning out all the debris immediately solved the leak problem.

You are right, it isn’t a very pleasant job. It took me probably 4 or 5 hours of work before I was finished. And very wet.

I’ve never tried this, but I wonder if a smoke tester or a good worklight (in the dark at night, with a friend moving it around and you watching for light leaking out where it shouldn’t be) would help disclose the leak.

Again, I’ve never tried either but I’m just trying to come up with a new approach. If you try one of these ideas, let me know how it works.

Windshield leaks are not uncommon. There’s a special “Silicone windshield sealer” (basically a thin silicone sealer) for this.

Diagnose it like a leaky tire. Get an air hose or a leaf blower or something and run it in the window with some duct tape and cardboard to seal it up. Pressurize the cabin. Spray the outside of the vehicle with soapy water. If you see bubbles where you shouldn’t see bubbles, that is your leak! Okay… I just totally made that up. MIght work. I dunno. Feel free to try it. :slight_smile:

When I bought my pickup truck, it had a little bit of a funky wet smell. I assumed it just didn’t dry that well after he shampooed the upholstery. It turns out there was a leak in the back window and a lake was forming under the back seat every time it rained! A girl at the window repair shop clued me into “flowable silicone”. It’s awesome stuff. It flowed right in like water and sealed everything up. The repair is completely invisible. And it’s cheap. And it was readily available at AutoZone.

+1, you need to remove the carpet and padding. Otherwise, it will get mildew/mold and destroy the interior. There will be gallons and gallons of water absorbed in those materials. No amount of fans and airing out is going to work based on my experience with a similar problem.

Once it’s out, line the sloping areas to the footwell with paper towels or that rolled paper like they have in bathroom dispensers. Now repeat your hose application, checking periodically for wet paper. Look up from there. You may have a firewall seam that is cracked. BTDTBTTS. Leaves packed a drain on the firewall of a GrandAm I had. It rotted out and leaked…

That flow-able silicone sealer seems like it would be a pretty useful sometimes. I’d never heard of it until now. Thanks for the info.

BTDTBTTS? I must be getting old. I get the been there done that, but what’s the rest (BTTS)? I’ll probably slap myself.

Bought The Tee Shirt?