Why Is There Water Leaking Underneath My Car?

Why Is There Water Leaking Underneath My Car? | Oceanworks Berkeley

You walk out to your car, start the engine, and suddenly, you notice water pooling underneath your vehicle. This can cause immediate concern. After all, a leak isn’t something any car owner wants to deal with. But before you panic, it’s important to understand that water leaking from under your car isn’t always a bad sign. In fact, in some cases, it’s entirely normal. So, what causes water to leak when your car is running, and when should you worry?

Air Conditioner Condensation

If you’ve ever noticed water dripping under your car after running the air conditioner, it’s likely just condensation. This happens when the AC system removes moisture from the air inside your car to keep it cool and dry. That moisture then drains out through a tube and ends up as a small puddle underneath your car.

You’ll usually see this water after a drive on a hot day when the AC has been working hard. It’s perfectly normal and nothing to be concerned about. Just keep an eye on it—if the puddle is only water and appears only after using the AC, you’re in the clear.

Exhaust System Drip

Another common source of water dripping from your car is the exhaust system. During the combustion process, your engine burns fuel and air, which produces water vapor as a byproduct. This vapor can condense in your car’s exhaust system, especially on cool days or when your car is warming up.

It’s typical to see water dripping from the exhaust pipe while your car is running, especially when you first start it up. However, if you notice more than just a few drops, or if there’s an odd smell or smoke accompanying the leak, it could signal a more significant problem like a blown head gasket. But for most drivers, a little water from the exhaust is no cause for alarm.

Coolant Leak

Unlike water from the air conditioner or exhaust system, coolant leaking underneath your car is a sign of a more serious problem. Coolant (or antifreeze) is vital to keeping your engine at the right temperature. If there’s a leak, it can lead to overheating and extensive engine damage.

To check if the leak is coolant, look for a few telltale signs. First, coolant is often brightly colored—usually green, pink, or orange—and has a slightly sweet smell. If you suspect a coolant leak, it’s essential to address the issue immediately. Continuing to drive with a coolant leak can cause your engine to overheat, leading to costly repairs. A visit to your repair shop is necessary to diagnose and fix the problem.

Windshield Washer Fluid

Another possible source of water-like leaks is windshield washer fluid. While not technically water, windshield washer fluid often appears clear and can be mistaken for a water leak. This fluid is usually stored in a reservoir under the hood and is pumped out to clean your windshield.

If you’re low on washer fluid or notice a consistent leak near the front of your car, it’s worth checking the fluid reservoir for cracks or leaks. Fortunately, this is a minor issue that can be resolved by replacing the damaged reservoir or hose.

When Should You Be Worried About Water Leaks

While water leaking from your car is usually no big deal, it’s crucial to be aware of when a leak could signal a more serious issue. If you notice any of the following, it’s time to take your car in for inspection:

  • The liquid has a distinct color or odor (other than clear water).
  • There’s a significant amount of water pooling under your car.
  • The leak occurs without using the air conditioner.
  • You notice additional symptoms like overheating or strange noises.

Addressing these issues on time can prevent more severe damage to your vehicle and save you money on repairs.


Not sure if that leak under your car is something to worry about? At Oceanworks Berkeley, our experts will inspect your vehicle and find the source of the leak. Call us today and keep your car running!

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