Water in Gas Tank Symptoms and Solutions Explained

May 7, 2024
Water in Gas Tank Symptoms

In the busy business world, whether you are in charge of construction vehicles, running a bunch of stores, or handling farm operations, one annoying problem we all face is water getting into our car's gas tanks. 

Suppose your delivery trucks are all set for a busy shift. Or your tractors are gearing up for farm work. Suddenly, an unexpected issue hits, and it's water causing trouble in the gas tank. It may seem minor, but it can complicate your plans and slow your business operations.

We must identify and promptly address the symptoms of water in the gas tank. The awareness of those particular symptoms and their solutions is essential for a healthy engine and smooth vehicle performance. This blog will highlight those primary symptoms and their practical solutions. 

What Causes Water to Enter the Gas Tank?

Water can sneak into your car's gas tank in different ways. Recognizing these causes is the first step in avoiding harm to your vehicle's fuel system and engine. 

The three most common reasons for water mixing in gas tanks are below.


Water can enter a gas tank through condensation. Condensation happens when the temperature changes. The air inside the gas tank expands and contracts, creating moisture. Over time, this moisture can build up and eventually turn into water droplets.


Infiltration refers to the process by which water gradually seeps into a material or space. In the context of a gas tank, infiltration can occur when water penetrates the tank's structure. Water can enter a gas tank through leaks and from contaminated fuel supplies via infiltration.

Faulty Gas Caps:

Another way water can enter the gas tank is through a defective gas cap that does not seal properly. It can cause rainwater or other external water sources to seep into the tank.

Furthermore, weak seals in a fuel tank can also permit moisture to enter, especially in wet climates.

Common Water in Gas Tank Symptoms

water in fuel tank symptoms

Detecting water in a gas tank can be tricky since symptoms are not always apparent. However, there are some signs to watch out for.  

Are you scared there’s water in the fuel tank? Symptoms include:

Difficulty Starting and Power Decrease.

A common symptom of water in the gas tank is poor engine performance. It might include rough idling, stalling, or difficulty starting the engine. Water disrupts the combustion process, making it hard for the engine to run smoothly.

Sputtering and Hesitation:

If there’s water in the fuel, your engine might sputter and hesitate when accelerating. The irregular combustion can make the engine sputter as the engine struggles to maintain a consistent acceleration.

Rough Idling and Misfires:

Most cars made in the last two decades use fuel injectors instead of carburetors. These injectors spray the required fuel into the engine's combustion chamber. If water mixes with fuel in the gas tank, it disrupts the density that injectors can handle. Ultimately, it stresses the injectors and leads to engine stalling and uneven firing of the engine cylinders.

Unexpected Engine Stalling:

At first, the engine may run fine for a few minutes. But over time, fuel combustion weakens, revealing the symptoms of water in the fuel tank. If there's a lot of water in the fuel system, it might even make the engine stop suddenly.

Unusual Fuel Smell:

If you notice an odd smell from the fuel, it could mean there's water in it. Water can change the usual gasoline smell, making it smell weird and unpleasant. This smell suggests water might be in the fuel system, so it's worth checking to avoid problems with your vehicle's performance.

What Happens if Water Gets in Your Gas Tank?

water in gas tank

Water in gas tanks can seriously damage vehicles because it's chemically different from gasoline and diesel. Preventing water from getting into the fuel tank is essential to avoid issues with your vehicle, such as;

Corrosion and Rust:

Water in the fuel tank starts a corrosive process that can cause rust and corrosion. This leads to big deposits of debris in fuel lines and spark plugs. The inside of the fuel tank is especially vulnerable, and over time, the corrosion can spread to other important parts of the fuel system. Corroded parts weaken the structure and might cause leaks and other problems.

Fuel System Failure:

Infiltrated water in the fuel system makes an ineffective blend. The weak mixture makes the engine less efficient, causing the engine to struggle more to generate the same power. As a result, you'll notice lower mileage, meaning you have to refuel more often and spend more on running your vehicle.

DIY Diagnostic Tests for Water Contamination

While professional diagnostics are ideal for precise evaluation, simple DIY methods exist to identify potential water contamination.

If you suspect water has contaminated your fuel supply, there are two ways to check for the presence of water. If either method results in a positive test for water in the fuel, your best action is to drain the fuel tank completely and refill it with fresh fuel.

Let’s understand the two tried-and-true DIY diagnostic tests for detecting water in fuel:

Visual Inspection Tips:

Drain a few ounces into a clear glass container for a simple DIY check on water-contaminated fuel. Let it sit for about 30 minutes to allow the fuel to settle. Water, being denser than gasoline, will form a clear bubble or layer at the bottom of the container. You can visually inspect the fuel for signs of water contamination by looking for an opaque, gelatinous layer beneath the gasoline. 

Using Water Detection Additives:

A reliable method for checking for water-contaminated fuel is to use water-detecting additives. Put a small amount on a dipstick or a wooden stick, insert it into the tank for a few seconds, and observe. If water is present, the paste will change color. 

Effective Solutions for Removing Water from Your Gas Tank:

Look out for water in fuel tank symptoms. You can implement the following solutions to actively mitigate the consequences and ensure the integrity of your fuel system.

Fuel Additives and Treatments:

Using specific fuel additives to disperse water is a proactive way to deal with water buildup in your tank. These additives break down water particles into smaller sizes, preventing the formation of larger droplets. They work by neutralizing water in the gas tank and preventing water-related problems.

Draining and Replacing Fuel:

If you think your fuel tank has water, take immediate action. Drain and clean the tank to remove any water, sediment, or contaminants. Then, slowly pour in new fuel, start the engine, and monitor its performance to ensure the tank is back in working condition.

Professional Assistance:

Seeking professional help is essential in case no DIY solutions work. Experts possess the expertise to address extensive water contamination issues effectively. They ensure thorough restoration of your vehicle's fuel system.

Fuel System Cleaning:

The ultimate solution to eliminate water from your gas or diesel tank involves thoroughly cleaning the entire fuel system. Diesel tank cleaning is conducted to ensure the tank is contaminant-free. 

Professionals use techniques like fuel system flushing to achieve this. Fuel system flushing involves carefully cleaning the fuel system to eliminate water, dirt, or debris. Moreover, they perform fuel polishing to enhance fuel quality by removing impurities.

Water Removal Products:

Water removal products are essential treatments for your fuel as they combat rust and corrosion. These products also prevent fuel line freeze and remove water, slime, and contaminants. 

Choose a suitable product and follow instructions to use a water removal product effectively. Add the recommended amount to the tank, start the vehicle to circulate treated fuel, and check for vehicle performance. Water removal products typically work swiftly, providing rapid relief from water-related issues.

Preventive Measures to Avoid Water Contamination

water in fuel

Understanding and implementing preventive measures help reduce the challenges associated with water contamination.

Here are some top-notch preventive measures:

Maintaining Fuel Quality:

Choose high-quality fuel and opt for reputable gas delivery services. Water contamination can occur even in storage tanks. So, storing the fuel in reliable above-ground fuel tanks is a good practice.

Above all, you must know how long you can store diesel in a fuel tank. This is to ensure that the fuel quality remains maintained, as holding it for an extended period in one place may affect its quality.

Gas Cap Care:

A well-maintained gas cap offers an appropriate seal and prevents water from entering the fuel system. If the gas cap is faulty or worn, timely replacement is essential to avoid undue circumstances.

Regular Vehicle Maintenance:

Regular inspection of your vehicle's fuel system can detect a problem immediately. This proactive approach also prevents water infiltration and maintains the fuel system's overall health.

Avoid Condensation:

Condensation may occur due to improper fuel fillings. You must keep the tank as full as possible to minimize air space and avoid condensation. Above all, refuel during cooler times of the day to prevent temperature changes that contribute to condensation.

FAQs (Frequently Asked Questions)

How much water in a gas tank will cause damage?

The extent to which water can damage a car varies based on factors such as the size of the gas tank and the water concentration in the fuel system. Even a small amount of water can adversely affect the engine. 

Can a little water in a gas tank damage the engine?

Tiny amounts of water can usually pass through the fuel system without causing damage. However, even a small quantity of water can begin to cause problems.

What are the risks of removing water from my gas tank by myself?

Removing water from your gas tank by yourself is risky. Mishandling can damage the fuel system or introduce contaminants, causing more harm. Doing it without experience may even lead to further damage or void warranty coverage. So, it's safer to seek professional help.

How often should I check for water in my gas tank as part of regular maintenance?

It's recommended that you check your gas tank for water weekly as part of regular maintenance. This ensures the timely removal of accumulated water and contributes to the proper functioning of the fuel system.

Is it safe to drive my vehicle if I suspect there is water in the gas tank?

Driving your vehicle is unsafe if you suspect water in the gas tank. It can lead to critical engine problems. It can also corrode fuel system components. 


Water in your car's fuel tank can cause various issues, such as decreased fuel efficiency and engine damage. Therefore, you must acknowledge the causes, consequences, and solutions for water contamination to ensure your vehicle's optimal performance and longevity. Moreover, you must also provide regular maintenance,  handle fuel carefully, and take preventive measures to keep water out of the fuel tank. 

However, if you have queries related to fuel contaminants or deliveries, we are here for your assistance. Fuel Logic is always at your service to answer your questions and address your needs. Whether it's about an emergency fuel delivery or any relevant need, make a call and place the order today!

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