What Are Common Causes Of Water Leaking From Under A Car? And How to Fix Them

Any unusual thing occurring in your car requires your attention. It may start as a small issue but if left unchecked may develop and cause more serious damage to your car. Also, some vehicle mechanical issues are dangerous.

Some car leakages are a cause for alarm and should be attended to immediately. Therefore if you notice water leaking from under your car, first try to establish the source.

There are many possible causes of water leakages from under a car. Most of the issues are not serious.

If you are not in a position to do so yourself, then get a professional to inspect your car. Avoid using your car until the source of the problem is known.

Causes Of Water Leaking From Under A Car

Sources of water leakages in your vehicle

When water is leaking from under your car, it is odorless, clear and not oily on your fingertips.

First off, what is the quantity of the water? If the water is a lot, then it is a cause for alarm.

There are various possible causes of water leaks from under a vehicle. The most common causes are three. The cooling system, the windscreen washer system or the exhaust.

The cooling system

The most common cause of car water leakages is water from the air conditioning system. Establish if the water leaks on days you don’t use the AC. It also depends on the weather and temperature.

Turn your AC on re-circulation switch instead of fresh air option. So that when moisture from the air lands and concentrates on the AC parts it won’t trickle down.

On the other hand, your AC system could be faulty and will soon stop functioning. A faulty AC will result in water leaks either inside the vehicle or under the vehicle.

Have a professional have a look at the whole AC and recommend a solution. It is important for the mechanic to check the condense pipe, air filters and condense drain pipe.

To avoid such issues in future, ensure your AC is serviced at least once annually.

Also read: How Much Does It Cost To Build A Car?

Wind washer system

The windshield washer reservoir is an easy system to maintain. The part is made from high-grade plastic and can last forever.

If the leak from under your car comes from the windscreen washer system, there is no danger to you or your vehicle but the problem needs to be fixed anyway.

The windshield washer system gets damaged due to accidents or when water instead of windshield washer fluid is used.

It is dangerous to drive around with a faulty windshield washer system. Get the washer fixed as soon as possible.

The Exhaust

The exhaust system of a car emits gases from the vehicle. The gases come out through the tailpipe to the environment. However, water can leak from the tailpipe of your car.

It is important to establish the cause of the leak immediately.

If you notice that water is leaking from your exhaust system, then organize to have a professional mechanic diagnose the problem.

Avoid using the car until it is inspected. The issue can eventually get worse and cost you lots of money. Worse still, the issue can be dangerous to the car user and other road users.

If diagnosed in time, you may be required to replace only a small car part or a few parts.

Causes of exhaust water leakages

There are about four main causes of water leaking from the exhaust system of a car

Water condensation

A normal engine combustion process usually emits water and carbon dioxide. When the engine cools down, some gases which had remained in the engine, usually leave the chamber. The condensation of these gases is responsible for water coming out of the tailpipe.

Water from the catalytic converter

A vehicle catalytic converter functions by reducing the size of toxic gases being emitted into the environment. In the process of converting the toxic gases into more friendly emissions, some little water vapor is formed which can come out as water drops through the tailpipe.

Engine heat due to cold temperatures

When a car is turned on, the engine generates a lot of heat. The exhaust also usually gets hot too. The heat from the engine and from the exhaust usually combines with the cold air to form small water droplets, which come out through the tailpipe.

But this is usually only a car startup issue and clears within a few minutes of running the engine.

Defective Piston

Water leakages as a result of a faulty piston is a serious issue. The good news is that it is easy to know a faulty piston because there will be smoke in addition to the water leakage, coming from the tailpipe. The problem can be the piston or its rings or both.

Sometimes you can also have a burning smell coming from the interior of the vehicle.

Therefore if you notice water combined with smoke and any strange smell coming from under your car, rush to get a professional mechanic to inspect your vehicle. You will most likely be required to replace the piston alone, piston rings alone or both the piston and rings.

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Is it water or some other fluids leaking?

A car has a variety of fluids for the smooth running of most of its parts. It is important to establish what is leaking from under your vehicle. Some of the fluids in your car include brake fluid, power steering fluid, coolant, oil, gasoline, and automatic transmission fluid.

Check the texture, smell, and color of the leakage to establish if it is really water leaking or other fluids. Check the texture by touching it with your fingertips to establish if it is oily.

There are many consequences of having other fluids leaking from under your car. The leaks can pollute the environment. Some of the fluids are toxic to humans and pets. It is also costly because the fluids were bought. And of course it signifies the possibility of a leakage in your car which needs to be fixed.


Left unchecked, a leak can lead to car mechanical problems including engine damage and failure.

Also, a fuel leak can be very dangerous if it comes into contact with an open fire.

If you notice any leakage in your car other than water, call a mechanic immediately and don’t operate the car until the problem is fixed. What could be leaking from under the car could be brake fluid and running the car can result in brake failure which is costly to fix.


It is important to follow the manufacturer’s recommendation as far as servicing your car is concerned. Servicing your car in time prevents many mechanical car issues from happening unexpectedly.

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