4 Causes of Water Coming Out of the Exhaust

(Updated on October 20, 2022)

In the normal course of events, you won’t see water coming from the exhaust system of the vehicle. But if you notice that your tailpipe is leaking or dripping water out from it, then it means your exhaust system must have water inside it. This is no reason to be alarmed because the cause is usually no big deal.

However, it would be a good idea to get this situation investigated and diagnosed by a professional mechanic if you’re not confident in your abilities. Otherwise, it could create a worse outcome that will cost you hundreds or even thousands of dollars.

In most of these situations, it will be no big deal. The worst case would normally be that you would have to replace a small component or two which will cost you a few hundred dollars. Below are some common causes of water coming from the exhaust in normal and abnormal conditions.

See Also: 9 Reasons Water is Leaking Into Your Car

Reasons Why Water is Coming Out of Your Tailpipe

1) Condensation (Normal Cause)

condensation from exhaust

After your engine has just performed the internal combustion process, there is a carbon dioxide and water mixture that forms as a result. Once your engine has been given some time to cool down, there are remaining exhaust gasses which leave the chamber and come out of the tailpipe.

The condensation of these gases is more apparent which means that you will be able to see the water dripping from the tailpipe.

2) Catalytic Converter (Normal Cause)

symptoms of a bad catalytic converter

When the exhaust system emits toxic carbon gases, the catalytic converter is responsible for reducing the size of these gases before they come out from the tailpipe.

This allows the vehicle to be more environmentally friendly while reducing the risk of harming other people in the process.

However, as the catalytic converter works to reduce these toxic emissions, there is a small amount of water vapor that forms as a result. This water vapor will form little droplets that will come out from the tailpipe.

3) Engine Heat (Normal Cause)

water from tailpipe

If you live in an environment with cold temperatures, you can expect to see water coming from your exhaust. The components of an engine normally need a little bit of time to let the oil circulate through them in order to cool them down.

In the meantime, the moving components of the engine are going to generate a lot of heat within the first couple of minutes after start up. The exhaust system is also going to be unusually hot too.

Because of this, water vapor is produced as the heat merges with the cold air. Then you’ll see small water droplets falling from the tailpipe along with a bit of what appears to be white smoke. Just wait a few minutes with the engine running and they should all clear up.

4) Faulty Piston (Abnormal Cause)

bad piston

It can be serious when a bad piston is causing water to come from your tailpipe. You’ll know if the pistons or its rings are the cause because you will also see smoke come out of the tailpipe in addition to the water.

If it is really bad, then a burning smell will fill the interior of the cabin. Either that or it might be a sweet aroma that would indicate an even bigger problem.

So, if you experience any strange smells along with smoke and water coming from your tailpipe, then don’t drive your vehicle. Have it towed to an auto repair shop and have them confirm it’s your pistons and/or piston rings and replace if necessary.

47 thoughts on “4 Causes of Water Coming Out of the Exhaust”

  1. I have my mechanic replace my cylinder head. But I still notice abnormal quantities of water coming out of my car’s muffler. May I know the possible causes?

    • Water out the tailpipe from a blown head gasket will appear as white smoke, and is pretty hard to miss if the leak is bad. If it’s just water droplets, this could be normal condensation. It’s possible you’ve always had this level of moisture coming out, but it is more noticeable after the repair because you’ve been paying more attention to the car. I know I tend to do this after I notice a problem.

  2. What if the vehicle runs 24-7 for weeks at a time? The vehicle is used for security purposes.What would the cause of water coming out of the exaust?

    • If the vehicle is used for security purposes you should really consult your own mechanic over an internet resource. It’s hard to know for sure without seeing it in person, but my gut tells me it’s probably fine if it’s just a few drops of water here and there.

    • There was spurt of water coming out of my exhaust pipe when I started my car, and the car shook when the engine started running. This happened about 5 seconds and then the engine ran smoothly.

  3. Car idles fine however when reviving to 2.5k rpm and releasing throttle. The car throw out quite a bit of water out of the exhaust as if its filling up then blowing it out. Also slightly smokey (white), is this the head gasket blown?

  4. My car is running really rough and is sluggish and has quite a bit of water coming out of the tail pipe but no smoke. Any idea what would cause this??

  5. I test drove a used car today. When I revved it up, lots of water from the tailpipe. Not a drip, pints of water. Dripped out when running, but gushed out when revved. No smoke. What would cause it.

    • It was probably just a lot of condensation. If the car was sitting, it’s not uncommon to see water out the tailpipe when you rev it up. If it’s cold, you’ll see more of it.

  6. i start the car and let it idle till it warms up, then rev it up a few times and a lot of water flies out along with white smoke. no water in oil. the car runs great. 2000 toyota camry 4cyl. engine.

    • A little water in the exhaust is pretty normal, as is a little white smoke if it’s cold outside. This happens when there’s condensation in the exhaust, especially after you first start the vehicle. If you’re concerned, have it checked out by a mechanic.

  7. I spent the night at a rest stop with my car running on and off for heat. When I started to take off I the morning water dumped out of my exhaust and there was white smoke for awhile. Water still drips out however there is no longer white smoke or very little. I am out of town and need to get home. Is it safe?

  8. I have a 1988 Jeep YJ Wrangler with a GM crate 350 HO in it and when I went to start it It knocked hard and pressurized water gushed out of the exhaust forcefully. I Immediately shut it down for obvious reasons and havent started it since. The engine has 5k miles on it. vandalism?

  9. I have notice when i have start a car water dripping throug tailpipe what is the reason my car engine is good condation or bad condation.plz tell me what is problem my car.

  10. Hi my rav 4 with 3s-fe it has a problem of water coming out of the exhaust manifold on cylinder number 4 only what could be the problem I have just overhauled the engine.

  11. A lot of water is pouring from my exhaust on my 2002 Denali, but without white smoke. And it runs fine, beautifully in fact, but the coolant level drops quickly and the engine will overheat.

  12. Recently a check engine light showed up on gauge when I started my car in the morning followed by sweet smell with water droplets from my exhausted and Am really puzzled with what that would be the cause????🤔🤔🤔🤔🤔💀💀💀💀

  13. Have a bmw 2013 328i, has a catless downpipe without a tune. 3 months after use only during cold starts the car spits out water that has like a yellow/brown colour to it. It’s not sticky or slimey. Is this condensation or something else ?

  14. my 318bmw f30 2016 model spits out lots of water and white smoke from the tailpipe, and it never stops. what could be the problem, some mechanics suspected the turbocharger but some ruled that one out. please help

  15. My 2012 pathfinder started spitting water out of tail pipe and muffler on startup. It’s a substantial amount. It wasn’t dripping all summer but started recently. It’s still warm. The water is coming out until the vehicle gets hot. It drips from the catalytic converter and muffler. I am worried the vehicle has a problem with the Cylinder head or a bad piston? It’s definitely water and not coolant. I do seem to have a very slow coolant leak also. The vehicle seems to be running fine. The mechanic Midas said it’s normal but I feel like it’s definitely the start of some issue. Please guide me

    • I am inclined to agree with the mechanic. Oil or coolant would be bad, but a little water is fairly normal. You can always get a second opinion if you think there’s something wrong, but if the car is otherwise driving OK I wouldn’t worry about it.


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