Water Leaking From Under Car? – Causes & Fixes

If you experience water leaking under your car, read this article to learn the most common causes and solutions to this common car problem.

Water Leaking Under Car

Why is water dripping under your car? It could be something simple, giving you nothing to worry about, but only a complete diagnosis will help you discover problems. For that reason, you must understand the times when it’s normal to see water leaking under a car and when it’s not.

In this guide, we cover the top causes of water under the vehicle, normal or not. We also walk you through the ways to fix an abnormal leak under the vehicle. If water is leaking inside the vehicle, we look at some causes for that as well. Finally, you get answers to a few of your top questions. 

Causes of Water Dripping From Underneath Car

If there is water leaking or dripping under your car, it could be from the air conditioning system, which is normal. It might also be caused by rainwater that’s been run over or condensation from the exhaust. More alarming, it could be a leak from something dripping inside.

Here is a more detailed list of the causes of water dripping or leaking underneath your car:

1. Air Conditioning System

Car Ac Condenser

When the air conditioning system is running in the car, it’s meant to drain out the bottom. Moisture is removed from the cabin, but that moisture has to go somewhere. The logical explanation is to have a drain that drips on the ground. 

This condition is one of the main reasons people notice water sitting underneath a vehicle. If the water is dripping towards the front of the car in a rhythmic pattern and the air is running, you can almost bet this is the cause. 

2. Rainwater

Underneath your vehicle, there are nooks and crannies everywhere. Within the metal chassis, water that gets run over on the road can pool in unusual places. If you have been driving through puddles or traveling in heavy downpours, you may see some water dripping underneath for a little bit.

This same condition happens after you drive through a car wash, especially if you choose to have the undercarriage washed. As long as everything feels normal and the water stops dripping, you have nothing to worry about. 

3. Exhaust Condensation

Exhaust System Car

The exhaust fumes coming out of the engine meet with ambient air and condensation occurs naturally. This water vapor can collect in the tailpipe and drip out from the car. Typically, you don’t see this water until the metal isn’t hot and it’s had the chance to cool down.

At first, the water coming from the tailpipe might stream out, but it should quickly slow down. Once you go for a drive and heat the exhaust back up, the dripping should cease. 

RELATED: Water Coming Out of the Exhaust Pipe? (Should You Worry?)

4. Interior Water Leak

The first problem worth worrying about is some sort of interior leak in the cabin. If there’s a broken part or something has failed, there could be a small flood in the car. If this happens, the water might be able to push through the cabin and start leaking outside. 

Water can leak from multiple areas, including the trunk, footwells and door jams. While this water might leak while you are driving, you probably won’t notice it until you stop. When the interior is wet, you should also smell some sort of damp or moldy scent. You may also hear some water sloshing around in the vehicle, especially as you hit a bump or take a turn. 

5. Windshield Washer Fluid Leak

Up until now, we’ve only looked at straight water leaking under the car, but there are some liquids that can be confused with water. One such liquid is windshield washer fluid.

Inside the molded container under the hood, windshield washer fluid is held, sometimes as a mixture with water. If something happens to this reservoir, the fluid can leak on the ground under the car. At first glance, you might think it’s water. Upon closer inspection, you should see the blue tint it has to it, making it easy to diagnose. 

6. Coolant Leak

Coolant Leaking E1609789888621

Coolant is another fluid that some people mistake for water. It’s no wonder why because a 1:1 ratio is typically used with antifreeze and water. Additionally, some people fill the coolant reservoir with water at times, even though they shouldn’t.

The car motor relies on coolant to maintain adequate temperatures. It’s needed to remove the heat and keep the engine at a normal operating temperature. If coolant weren’t present, the engine would overheat and you would have big problems on your hands.

If you see liquid dripping under the car, take a quick look at the temperature gauge on your dashboard. Additionally, you can spot coolant by the color and scent of the fluid. It’s normally slightly colored and it will have a distinct sweet smell. 

What’s more alarming is if you see a water-like substance coming out of the exhaust with white smoke. This fluid is probably coolant and indicates that the car could have a blown head gasket

RELATED: 5 Causes of a Coolant Leak – How to Fix it & Repair Cost

How to Fix Water Dripping Under Car

If your car is leaking water underneath the car, you first want to inspect the leak to ensure it’s water and not another fluid. If it’s water, you want to check so it’s not just normal condensation dripping from the car’s AC.

1. Determine What is Leaking

Before you move forward, you want to be sure you are dealing with water. If the problem is water, you probably aren’t looking at anything major.

On the other hand, if you have mistaken the fluid for water when it’s not, the problem could be something severe. For that reason, you need to completely examine what color the fluid is.

Here are a few colors you might see under the car.

  • Clear: water
  • Blue: windshield washer fluid
  • Green: coolant/antifreeze
  • Orange: coolant/antifreeze or transmission fluid
  • Yellow: coolant/antifreeze
  • Pink/Red: power steering fluid or transmission fluid
  • Brown: Gear lubricant, engine oil or brake fluid
  • Black: old engine oil

To see the color, you can use a piece of paper or cardboard under the leak. Once it drips, you’ll have a better idea about what you are looking at. 

RELATED: Car Leaking Fluid? (How to Identify The Liquid)

2. Determine Where The Leak is Coming From

Once you’ve identified what is leaking, it’s time to figure out where it is coming from. Start by placing a large piece of cardboard under the car. Once the fluid leaks, you will be able to match up the location with where the leak could be coming from.

For example, if you see water dripping from the front, you are probably only dealing with typical air conditioning leakage. If it’s coming from the exhaust, this might be result of condensation. 

3. Repair Leak

If you find a malfunction, you must repair the problem before bigger problems occur. For example, if you find that the leak is coming from inside the cabin, you need to track it down and fix whatever is wrong.

Additionally, if coolant is what is leaking, it’s best to get it repaired right away before the engine starts overheating. If you don’t feel equipped to diagnose or repair the problem, take your vehicle to a qualified professional. 

4. Test Out

Whatever fix you perform has to be tested out. At first, you want to continue putting a piece of cardboard under the car to make sure there’s no more leak. 

Even after you remove the cardboard, it’s best to keep your eyes peeled for trouble. Once you feel secure that everything is resolved, you can focus your attention elsewhere. 

Why Does Water Leak Into the Cabin?

1. Clogged Evaporator Drain

There’s an evaporator drain built into the AC system to ensure the moisture drips out slowly under the car. If this drain becomes clogged, the water won’t be routed to the right location.

Because of this clog, water starts to back up into the cabin. By cleaning out the dirt and contaminants with compressed air, you can open the drain up once again. 

2. Damaged Heater Core

Debris can also get into the heater core, although it’s not a common occurrence. When condensation occurs, the debris could create corrosion and rust within the core.

If this happens, leakage could occur. Other symptoms you might notice include a colder cabin or a foggy windshield. However, when this occurs, antifreeze is what is leaking in the cabin, so you should smell something sweet. You will be forced to replace the heater core at this point. 

3. Leaking Windows/Sunroof

If there’s any defect with the automotive glass, leaking can occur. Most of the windows, sunroof and windshields are held in with rubber seals that can crack over time. Additionally, drain holes around the windows can become clogged.

If water is dripping in through the glass, open up any drain holes first. From here, you should examine the rubber seals to ensure everything is intact. Beyond that, you might need to have new glass installed if there’s a physical defect. 

4. Failed Weather Stripping

Around the doors is also weather stripping that keeps moisture out. From continued friction, this weather stripping can crack and wear out. 

You will also find this weather stripping around the trunk. Typically, it’s simple to replace the rubber material, but you want to use caution. 

FAQs

Is It Normal for Water to Drip From Under the Car?

More times than not, the dripping water is a normal occurrence. It can be dripping from the AC system or the exhaust condensation. However, there could be some problems that need to be resolved if the dripping isn’t from normal operation. 

Why Would Water Be Dripping From My Car?

When the AC system or exhaust creates condensation, this liquid has to drain somewhere. It will form a small drip under the car. However, there could also be a leak inside the cabin that’s coming out or a mechanical failure that mimics the look of water, even though it’s another fluid. 

Should I Be Worried About Water Under My Car?

You should always be willing to inspect anything that’s dripping from your car, but you don’t need to be immediately alarmed. If you are sure the fluid is water, it’s probably from normal operation unless the water is leaking out of the cabin. Other fluid leakage should cause more panic and provoke a quick fix.

What Are the 3 Most Common Liquids Found Underneath the Vehicle?

Water is a common fluid found under the car, especially after the AC system has been running or if there’s condensation in the exhaust. Additionally, coolant and oil can leak under the car when there’s a mechanical issue that demands your attention. 

Conclusion: Leaking Water Under Car

If you see water dripping from under the car, don’t panic. Walk through the steps to diagnose what’s going on and hopefully, it is caused by normal operation. Even if there is a problem, you can get it repaired, so you can head back out on the road.

Learn more:

Brian Jones
Written by:

Brian Jones is a writer and owner of a used car dealership in the Dallas, Texas area. While he loves just about everything automotive, he has a special place in his heart for trucks, the bigger the better. In his spare time, he enjoys traveling with his family and hiking new trails. ASE Certified Master Technician.

Related Posts