Water Contamination in Diesel Fuel: How Can You Remove it and Prevent it?

Fri, Nov 10, 2023

Water inside fuel storage tanks is a serious issue for diesel engines, generators, vehicles, plant equipment, and boilers.

*With over 25% of generator breakdowns being caused by bad fuel and not a mechanical failure, and **8 out of 10 diesel engine failures caused by diesel bugs in fuel, it’s important to understand how and why you need to remove water from your fuel tank fast.

So, what does water in your fuel tank actually mean?

Water Contamination in Diesel Fuel

What does water in fuel or the fuel tank mean?

Diesel is hygroscopic, which means the fuel will attract and hold onto water often caused by condensation at a molecular level. The amount of water absorbed will vary depending on the temperature, air humidity and biodiesel content. Water droplets will then start to sink to the bottom of the tank when the fuel reaches maximum saturation percentage, and it is here that diesel bug sludge grows.

You might start to notice water in your fuel tank if your equipment has these symptoms - hesitation and spluttering when accelerating, difficulty reaching higher speeds and murky looking fuel with low opacity. These all sound pretty nasty, but will they result in damage to your engine? Let’s take a look below.

Will water in the fuel damage your engine?

Fuel maintenance and correct storage conditions can help reduce the risk of fuel contamination from diesel bugs, water, and sludge, all of which can degrade your fuel’s quality and eventually get into equipment and machinery, blocking fuel injectors and damaging other parts of your engine or boiler.

Degraded fuel can also cause internal tank corrosion which can damage dispensers, block filters, and eventually lead to a halt in operations, so you need to fix and prevent water in fuel urgently if you are aware of it.


blocked fuel filter

How can you fix and prevent water in fuel?

Regularly replacing filters stops sludge getting into the machinery before dispensing. Filters are designed to catch and hold water and the diesel bugs it creates. Fuel tank filters such as the Goldenrod and Cim-Tek filters are designed to be fitted outside of a diesel storage tank, but they do not prevent water or sludge from forming inside the tank before reaching the filter.

To remove water from inside the fuel tank and stop contamination we recommend Aquafighter. This fuel tank water absorber removes suspended and emulsified water from the fuel and supplies a complete solution for water contamination. Aquafighter reduces the water content levels down to less than 75ppm, which exceeds the EN590 diesel fuel standards of 200ppm, making it the best on the market for fuel tank water absorbers.

The Aquafighter works by being placed in the tank through the largest opening, and then forces a chemical reaction that separates the bound water from the fuel molecules. The water absorber then catches the water in the fuel inside the fabric membrane by bonding it to a special polymer. It can then release the clear diesel fuel back into the tank.


Aquafighter Tank Water Absorber

A fuel circulator can also prevent diesel fuel inside a storage tank from getting stagnant, which can happen when there is low usage such as in generator back up tanks. When fuel sits stagnant for too long, diesel bugs form in the space between the free water at the bottom of the tank and the diesel.

The CTS fuel recirculation unit draws the fuel up from the front of the tank through the magnetic conditioner and breaks down the sludge to a size that will pass through a two-stage water and particle filtration process to remove any impurities. The cleaner fuel is then circulated back into the tank, stopping sludge forming.

If you want to deal with your water contamination head on, the Aquafighter is the complete solution. Once the Aquafighter water absorber is in your fuel tank, alongside a filter, you can have peace of mind that your diesel fuel is always water-free and ready to dispense.


*Water in diesel? Fuel contamination in diesel and gas oil (tankservices.co.uk)

**Diesel Bug Guide - Spot, Fix & Prevent Fuel Bug | Crown Oil

Ready to Remove and Prevent Water in Your Fuel?

We are the UK agent for the Aquafighter water absorber range; the best fuel tank water absorber that removes both free and emulsified water from your fuel.