How to Fix Water in Gas Tank (5 Symptoms and Effects)

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Vehicles require gas or fuel to run efficiently. If water accumulates in a vehicle’s gas tank, problems will arise. The presence of water damages fuel injectors causing them to perform poorly and, eventually, fail. This article will describe how to determine and fix water vehicle’s gas tank and, if necessary, how to address the problem.

5 Signs That There Is Water In Your Gas Tank

Possible reasons why water enters the tank include: Frequent condensation due to temperature changes, a failed or leaking gas cap seal, a contaminated or dirty gas tank, a cracked filler pipe or malicious intentions of others.

There are several signs to look for in a vehicle with water in the gas tank. If a vehicle owner notices any of these signs, they should be addressed promptly.

Also read: P0457 Evaporative Emission Control System Leak Detected

1. Hydrolock

If there is too much water in the gas tank, the engine will hydrolock. This means that water enters the combustion chamber of the engine and the gasoline cannot efficiently burn. If the spark plugs don’t get enough fuel to ignite, the engine will stall. The water inside will be preventing the compression and combustion of the gas making it very difficult for the engine to start.

2. Engine Starts But Stops

If there is water in the gas tank, vehicle owners may notice that when they turn on their vehicle, it starts and then immediately stops after a few seconds. This is another sign of water in the gas tank. As mentioned above, this is due to the engine hydrolocking which causes the vehicle to stall. It can also cause it to run roughly, if at all, once it is started.

3. Engine Does Not Start At All

If there is a significant amount of water in the gas tank, the vehicle owner may notice that their vehicle does not turn on at all. This is because when there is too much water in the gas tank, the combustion chamber of the engine hydrolocks preventing it completely from firing or starting. As a result, even with the ignition on your engine will not start. However don’t immediately jump to this conclusion as this could also be a symptom of you simply being out of gas.

4. Reduced Fuel Economy

If there is water in the gas tank, you may notice your vehicle is running sluggishly or you have reduced fuel economy. This happens due to the water in the gas tank reducing the power of the engine. While the amount of gas burning will remain constant, you will get less mileage from your car. In the end, you’ll end up consuming more gasoline while receiving a poor return.

As water in a gasoline tank hinders the car’s performance and causes the fuel to degrade. Microbial growth can clog the filters, resulting in the system’s complete failure.

Aside from that, since water will settle to the bottom of the tank, this may cause your gasoline tank to corrode, eventually forcing you to replace the tank.

5. Reduced Acceleration Speed

While you may notice something fishy when you first start up the car, the symptoms will be most apparent while driving and accelerating. If your vehicle is not functioning correctly, you may notice minor speed adjustments that you are not doing while driving it. This might also manifest as a form of sputtering. If your car stutters when you step on the gas but you actually have enough fuel, you should check to see if your tank is contaminated with water.

Also Read: Why Does my Car Sputtering When Starting

How to Get Water Out of Your Gas Tank

Source: Motor Biscuit

Now that we have discussed the signs and symptoms of a gas tank with water in it and know how to identify it, we will go over how to get rid of the water.

1. Drain the Gas Tank

As soon as you notice there is water in your gas tank, you should remove the rest of the gasoline from the vehicle. Be careful though, remember gas is flammable and you don’t want it anywhere near an open flame.

As gasoline is lower in density than water, it will stay on top and the water will drain out first. Make sure to drain out everything completely, you should not risk leaving behind any water or else it will cause these problems again. Allow the gasoline to drain for a long time to be safe.

If your tank doesn’t have a drain, you’ll have to do things the hard way. It might be emptying the tank or siphoning out the gasoline. The latter is a bit more difficult and time consuming but effective all the same.

2. Replace the Fuel Filter

After you have removed the rest of the gasoline you should consider replacing the fuel filter. This way you will be sure that your vehicle and gas tank won’t be exposed to contaminants like before, as the fuel filter most likely must have disintegrated or weakened, due to water damage, causing it to become ineffective and vulnerable to debris and dirt. Not replacing it may cause further problems such as having to rebuild the entire engine due to excessive damage, thus it is very much worth the price.

3. Flush Fuel Lines

Leakage in these lines can be a serious problem. Though hard to detect, if this happens, you are risking a fuel leak that might cause a fire. This is a large problem that you should bring to the attention of a professional mechanic, as it can be quickly, properly and easily fixed by them. As fuel lines are meant to conduct gasoline, they aren’t designed to be able to withstand water and will weaken. So be aware of this vulnerability and make sure to get them checked out if you suspect a problem.

Also read: How To Test A Gas Cap For Leaks

4. Fill Up Gas Tank

After you have flushed out everything and have made sure all parts of the engine are in perfect working order, you may fill up the tank with fresh gasoline. Be sure to follow the usual precautions when refuelling your car and you’re good to go!

Frequently Asked Questions:

How to avoid having water in the gas tank?

A gas tank will always have a tiny amount of moisture as a result of condensation. A little water in the gas tank is nothing to be concerned about. However, you should be worried if the water content in the gas tank rises. You can prevent this from happening by taking a few precautions.

Firstly, keeping the vehicle’s tank full on a regular basis will reduce the amount of water in gasoline. Keep an eye on your gas level and fill it up whenever it gets low. This will reduce the amount of water in your tank and keep it from settling at the bottom.

Secondly, regular inspections will ensure that there is no water in your gas tank. This can also include taking a closer look at the opening into which you insert the fuel pump‘s nozzle when filling the tank. The majority of today’s automobile fuel systems are designed to prevent humid air, as well as other potential hazards, from getting into your gas tank in the first place. Make sure you have a good one and that there is nothing obstructing the fuel tank’s opening and that it’s clean. Inspect your vehicle regularly and look for signs of leaks or damage.

Lastly, if possible avoid filling gas from a cheap gas station. Gas stations may offer lower prices in an attempt to attract customers and this might result in using lower quality gasoline, or even using water as a filler. So beware of those scams.

Also Read: How much does it Cost to Replace a Fuel Pump

Is it safe to drive the car with water in the gas tank?

If the amount of water in the gas tank is low and it hasn’t reached critical levels then driving with a small amount of water for a short distance to the mechanic in order to get it fixed should be fine.

However, you should avoid pushing your luck. If the water content has reached a considerable level then it may be dangerous to drive as the water could interfere with the engine’s function causing dangerous and serious issues.

It is best to get the tank flushed at the earliest opportunity possible to make sure that any excess water does not damage the car’s engine.


Water in the gas tank is not something that can’t be dealt with. By acting quickly and hiring a professional mechanic to help you with repairing the problem, you can save yourself a lot of hassle and money.

By reading this article you are now better prepared on how to deal with water in a gas tank causing problems, which will ensure your safety and save you from huge repair bills.

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