Water Leaking Into a Car
If you have water leaking into your car, you need to deal with it promptly because of the many serious problems it can cause. If water sits for too long in a car's carpet, mold can grow and cause bad smells. Other problems can include corrosion of pin connectors, computer failures, sensor failures, rust, and high humidity inside the car causing your windows to fog up.
Where Is the Water Coming From?
A wet carpet is not the only sign of water leaking in a car. If you have an idea of where the water is getting into the car, check for water marks, stains, or even signs of rust. Take a close look at connectors for corrosion and check brackets for rust spots; you will be amazed what you will find when you look for it.
I have always said, "Mechanics' best tools are not found in their toolbox, they are found in their heads." Water leaks are hard to pinpoint, but once you find exactly where the water is coming in, you can access the problem spot and repair it.
Leaks From Outside the Car
The number one cause of a water leak in a car is the poor installation of a windshield. If you have had a windshield replaced recently, take a look at this possibility. I'm not trying to disrespect windshield replacement companies, it's just that some companies hire people who just don't care; they will cut out the old windshield and slap in the new one without proper preparation.
If a professional replaces the windshield, it will take a minimum of an hour. It takes time to remove the moldings, cut the windshield out, trim the old urethane so the new windshield sits flat, touch up any scratches in the paint from the removal process, prime the glass with a primer, and install a nice bead of new urethane.
If your "professional" replaced the glass in just 15 minutes, his or her work might be not just the cause of a water leak but a safety issue. In the event of a car crash, you could be thrown through an improperly installed windshield and severely injured. I am good friends with a guy who owns his own windshield repair company, and I see and hear the horror stories, so I write to you from experience.
2009 Honda Fit Water Leak in Hatch Area
Leaking Body Seams
Body seams are the second major cause of water leaking in your car. Seams that weren't properly sealed at the factory, or seams that were broken open by a car accident, will usually cause the mystery water leak. Finding the point of entry is worth the struggle.
Once you find the seam that is leaking, I recommend using on the problem area. This is the same sealer auto makers use in the factory to seal all seams in the body of the vehicle after they are welded. One reason I like to use this seam sealer is that it skims over in about 30 minutes, so you don't have to wait a long time between water tests. Nevertheless, if you can let the car sit overnight after sealing it, the sealer will adhere to the body seams completely, and you won't have a seam open again because of the body flexing before the sealer is completely dry. 3M Brushable Seam Sealer
Water-Testing Your Car for Leaks From the Outside
Finding the point of entry is the first step in keeping rainwater out of your car. This investigation is time-consuming, but something you can do yourself. You need to physically see where the water is coming into the car, not just where it is traveling along a panel or a seam. To test your car, pour water on it: start at a low point and work your way up to the roof. If you determine that water is leaking into the bottom of the windshield, there is no need to go any higher with the water test until after you've fixed this first low leak.
Leaks Into the Trunk
A foul, moldy smell in the trunk may result from water getting in around the taillights or the trunk lid. If you can identify these leaks you can get them fixed.
How to Check Sunroof Drains
Leaking Sunroof: Finding Clogged or Disconnected Sunroof Drains
Subaru Legacy Sunroof Water Leak
Leaking Aftermarket Accessories
Poorly installed aftermarket accessories are another major cause of water leaking in your car. Anything from a sunroof to a roof rack system, if not installed properly with the right sealer, will cause a water leak in a car.
If you have a factory-installed sunroof, check the drains. Sunroofs leak! That's why a factory-installed sunroof has a built-in tray with four drains, one in each corner of the sunroof. Sometimes these drain tubes become disconnected or clogged and will cause water to leak into the car. Locating the drains and checking them for proper drainage can take some time because they are usually buried in fenders and body panels, but it's time well spent. A shortcut to locating the drains is to fill the sunroof tray with water and watch where it goes when it drains. It will usually spill out in the front and the rear of the rocker panels.
Leaks From Inside the Car
Some leaks into the passenger compartment happen when it hasn't even been raining; they involve fluids created by the car's cooling or heating systems.
Clogged Air Conditioner Drain
When air conditioners take humidity out of the air in the passenger compartment, they end up collecting a lot of water that has to drain out of the car. Water dripping out of the air conditioner drain onto the ground is totally normal; water dripping onto the floor of the car from the air conditioner is not. If you haven't had any rain, and you have water leaking onto the passenger's floor, check your air conditioner drain or evaporator drain; it may be clogged or disconnected. Debris gets sucked into the evaporator from outside and occasionally will clog the drain tube. A temporary quick fix for this problem is blowing compressed air into the drain tube located under the car, but eventually you will have to remove the evaporator and clean out the debris.
Leaking Heater Core
Another possible cause of wet carpet, especially in the front of the car, when it hasn't been raining, is a leak from the heater core. Car heaters circulate coolant through the dashboard area to heat the car, and if the heater core springs a leak, coolant can drip onto the floor.
How to Find Water Leaks in a Car
Let's Share Information
I hope this has given you some insight on water leaks and a few ideas on where to start looking. If you have a question about water leaking in a car, leave it in the comment box below, and I will answer it ASAP.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
I have water on the passenger floor of my 2011 Hyundai Sonata. Could this be a clogged drain in the sunroof?
More likely the drain on the evaporator is either clogged or knocked off. If that looks ok it could be a sunroof drain or a windshield gasket. Have you had your windshield replaced recently?Helpful 86
I have a 2016 Ford Fiesta. I just got it brand new a year ago. This morning, I found the floor on the passenger side (behind the driver) soaked in around 5-7mm of water. I’m sure it didn’t rain yesterday but it rained hard two days before. The other side of the passenger, seats and the driver floor is dry. What could be causing this?
I recommend bringing it back to Ford; I think it may still be under warranty. There are a lot of things that can cause this, leaking body seams, missing door seals, tail light seals, sunroof drains, etc. I recommend checking the trunk for any signs of water as well.Helpful 22
Water leaks into my car from under the glove box. How do I fix this problem?
Water is leaking in from under your glove box because you either have an evaporator drain that is clogged, or you have some other leak. You'll need to find the point of entry by either water testing your vehicle, or try unclogging the evaporator drain by using a coat hanger or compressed air up the drain tube.Helpful 47
After I spray water on my windshield or after I carwash it there's no leak inside my dashboard, but when I drive it and take a sharp turn some water leaks under my dash on the passenger side floor like there's a container overflowing. How can I find out from where the water is leaking?
It sounds to me like your air conditioner evaporator is not draining and is leaking water onto your passenger side floor. I recommend finding the AC evaporator drain and clearing it with a coat hanger or a piece of flexible wire.Helpful 6
I have a 2001 Toyota RAV4. The driver side floor is soaking wet after the rain. How do I find and fix this issue?
I recommend pulling back the carpet and water testing it to see where the water is entering the vehicle. Water leaks will usually leave a trail or debris or rust so you can look for signs of this before you even water test.Helpful 11