Pee in a Gas Tank: What REALLY Happens?! (Explained)

If you are curious about the things that can damage an engine, you probably come up with the idea of peeing in the gas tank. While there are so many possibilities on what you can put in the gas tank, you may wonder if pee or urine can do some significant damage. So, you may ask:

If you pee in a gas tank, what really happens? If you pee in a gas tank, chances are it won’t do that much harm. A person’s urine won’t hurt the engine, especially if it mixes with the fuel. Urine contains salt, though, which means it can cause rust. Your pee would likely sit on the bottom and continue doing its damage if you don’t take it out soon.

While a person’s urine won’t cause significant damage immediately, it’s still not something you can take lightly. Since urine contains destructive properties to the fuel system, you need to be serious in dealing with such if it ever happens to you.

In this article, we’ll walk you through the effects of pee in a gas tank, as well as the common problems you may encounter due to such. This way, you can understand what it means and learn how to deal with it if it ever happens to you.

Without further ado, let’s get into it!

Pee in a Gas Tank

What happens if you have pee in a gas tank?

If you pee in a gas tank, it may cause quite a lot of mess and damage to your engine. In general, the effect of pee in a gas tank will vary on how much pee it gets.

For instance, a pee from one person won’t likely hurt a gas tank filled with fuel. But, of course, it can lead to contamination in the long run. Again, however, it’s not something that will cause significant damage soon.

Moreover, a single person’s urine can get solved by adding a fuel additive such as the B12 Chemtool to clean your fuel system.

Here are the short and long-term effects of pee in a gas tank:

Short term effects

A pee can affect the engine in a short while if you pee quite a lot and continue running your engine without adding fuel additives or cleaners.

Pee or urine contains ammonia and even salt, which means it can be harmful to your engine. However, if you’re thinking of immediate effects, the pee won’t likely cause any issue.

Moreover, it will likely get burned in the combustion chambers should it ever reach the engine. Of course, if it reaches the engine, it can cause stalling due to the poor combustion effects it can bring.

It is now possible to stop an engine by gathering many individuals and allowing them to all pee in a gas tank.

In most situations, the urine will clog the fuel filter, causing the engine to shut down. However, too much pee will cause the engine to run rough if it gets past the fuel filter.

Long term effects

The only long-term effects that pee can cause are corrosion and degradation of the tank due to corrosion and fuel contamination.

The thing about urine is that it contains ammonia and salt. While these two components won’t affect an engine’s performance if they don’t reach the combustion chambers, they can wear down the tank by inducing rust and corrosion.

For this reason, you need to get rid of the urine as soon as possible. This way, you can maintain your fuel system’s overall health and performance and your whole engine.

Can pee in a gas tank damage an engine?

Yes, pee in a gas tank can damage an engine. Most gas tanks are made of steel, and it means the ammonia and salt in urine or pee can cause corrosion or invite rust.

A single person’s urine may not harm the engine. However, it’s still not a good thing, and you need to remember that it’s not something you want to have in your gas tank.

Since urine contains water, salt, and ammonia, it can encourage rust, and it can happen if you don’t take it out and let it sit there for some time.

How much pee in a gas tank will ruin it?

As mentioned earlier, a single person’s pee won’t cause any issue. However, if the pee fills the tank, it can permanently disable the engine, and you’ll need to have it cleaned thoroughly. 

Pee is ammonia-based and, in most cases, will burn through your engine. However, if there’s quite a lot of pee in the tank, don’t even bother starting it, as it will only cause more harm.

Can you tell if someone peed in your gas tank?

Pee in your gas tank can lead to several issues, and such issues usually come with symptoms such as the engine shutting down or coughing up. Or, your engine could also start stalling once it has peed in the engine.

The thing to remember about pee contains ammonia, salt, and water, and all these three won’t complement your gas tank.

In most cases, the pee will remain at the bottom and can lead to rusting. However, it can cause a flawed combustion process if it reaches the engine and can lead to stalling.

Thus, if someone pees in your gas tank, you can immediately feel the effects once the pee reaches your engine.

Now, once you realize it has some problems, turn the engine off and have it checked. Then, if you have no idea what to do, you can continue reading.

pee in gas tank

How to get the pee out of a gas tank?

If you only have a small amount of pee, you can simply get it out of the system by adding a fuel additive like fuel tank cleaners. Such products are available online, and you can get them to clean your tank without taking it out and cleaning it thoroughly.

Now, if your tank has quite a large amount of pee, you may need to take it out, empty it, and clean the lines and fuel system. You will also need to replace the fuel filter eventually. 


In a nutshell, you should know that pee in a gas tank is not good for your engine nor your fuel system. It’s unlikely that peeing in a gas tank will cause any harm. The engine will not be harmed by a person’s pee, especially if it mixes with gasoline. However, because urine includes salt, it might promote corrosion. If you don’t take it out quickly, your urine will most probably settle on the bottom and continue to cause harm.

Although a person’s urine will not cause immediate harm, don’t take it lightly. Because urine has bad qualities for the fuel system, you must take severe action if this happens to you.

As always, do your best to solve such matters soon if it happens to you. This way, you can prevent further issues from building up due to leaving such minor problems unattended.



Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more