5 Reasons Why Water is Coming From Your Car Exhaust

Last Updated on June 16, 2020

The internal combustion engine of a vehicle emits exhaust gases during its combustion process. It would be bad if those gases were to stay in the engine which is why cars are built with an exhaust system.

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This is basically piping that allows the exhaust gases to flow out from the engine. The piping leads the exhaust gases all the way through the tailpipe and out into the atmosphere.

Sometimes you will notice water coming out of the tailpipe. This means that water is coming from your exhaust system for some reason. You don’t necessarily have to panic when this happens because it doesn’t always mean there is a problem.

You just need to understand all the possible reasons for why there would be water coming out of the exhaust. That way, you can recognize the signs for what they are. If it does happen to be serious, then you will be able to tell on your own before taking it to a mechanic.

Top 5 Causes of Water Coming Out of Your Tailpipe

#1 – Engine Water Condensation

white smoke blowing from exhaust

When your engine goes through the internal combustion process, there are various pollutants that form. The three main pollutants are water vapor, nitrogen, and carbon dioxide.

As the exhaust gases are leaving the chamber, the carbon dioxide and water are getting mixed together. The more the engine cools down, the water condensation in the exhaust becomes visible to those from the outside.

The tailpipe will have small drips of water coming out of it. When this happens, you have nothing to worry about. The water drips should stop within a couple minutes once the vehicle is warmed up.

#2 – Hot Engine

car shakes when stopped

Your engine will generate the most heat when you first start your car. The oil in the engine still needs time to flow and lubricate the components to cool them down. But, while the engine is hot, the exhaust system will be hot as well.

This will create water vapor in the exhaust if the temperature outside is cold. As a result, water droplets will come out of the tailpipe for a couple of minutes and then clear up. If they don’t clear up, then it could mean big trouble.

#3 – Catalytic Converter

bad catalytic converter symptoms

Every car has a component called a catalytic converter. This component lowers the amount of toxic gas emissions being emitted from the exhaust system.  That way, the emissions are not as harmful to the environment or people.

During the conversion process, traces of water vapor are produced. This will result in water droplets falling out of the tailpipe which again should go away on its own and perfectly normal.

#4 – Head Gasket Failure

bad head gasket

The first three reasons listed here are generally no cause for concern. The time when you should start worrying is if the water coming from your exhaust is caused by blown head gaskets.

Blown head gaskets will often manifest as white smoke coming out of the tailpipe. You may also notice air bubbling in the coolant reservoir and overheating issues. This issue should be addressed sooner rather than later. An overheating engine can cause all sorts of issues, and may even leave you stranded.

#5 – Bad Pistons or Rings

symptoms of bad piston rings and valve seals

A bad piston or worn piston rings will generally not cause water out of the tailpipe unless the head gaskets are also blown, or there is residual condensation in the exhaust system. However, bad pistons or rings will cause excessive blow by, which could create sooty exhaust, blue smoke, or oily residue around the tailpipe. 

As with blown head gaskets, you don’t want to let this one go too long without a repair, either.


Most of these reasons are due to water vapor effects. If it is cold outside in your environment, your tailpipe and the other components of your vehicle are going to be cold. This means that the heat generated from your engine while it is running will cause water condensation to form wherever there is water vapor present.

Since water vapor is commonly found in the exhaust system, then this is why so much of the water condensation flows out of the tailpipe.



  1. Your pistons and rings are not what’s causing water vapor to come out of your exhaust no matter what. What you mean is, your head gasket is bad that’s the only reason why water should be getting into your exhaust other than normal, than normal condensation.

    • Good catch, thanks. You are correct: in the case of bad rings, it would actually be oil coming out of the exhaust, not water. I’ve updated the article.

  2. So I have to ask where all of my coolant goes?
    Not in the oil Pan nor tans pan
    Bubbles and pressure from a cool system
    Engine clatters and loses power
    Have I went too far with my problems?


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