Diesel in your motorhome water tank? What to do and how to clean it

Filling the wrong tank when refuelling a motorhome or campervan may seem hard to imagine, but a moment’s distraction is all it takes to end up with diesel in the water tank instead of the fuel tank. When it happens, acting correctly is essential to remove the hydrocarbon residue and restore the system.

Draining the tank straight away is the first instinct, but it may not be enough. Diesel can come into contact with the tank walls and, if it has circulated through the system, it can also reach the pipes and other components.

That’s why, after accidental contamination, it’s important to carry out a specific clean of the whole system and not to use the water again until the problem has been properly treated.

What to do if you’ve put diesel in the water tank

If you find that diesel has got into the fresh water tank, the first thing to do is stop using that water, whether for drinking, cooking or showering. From there, these are the steps to follow:

1. Switch off the water pump and don’t open the taps until you treat the system, so the diesel doesn’t get from the tank into the pipes.
2. Drain the tank as soon as possible. The longer you leave diesel in the water tank, the more it soaks into the tank walls.
3. Treat the tank and pipes with Ambiti Gasoil Stop: 500 ml with the tank filled with water to three quarters, a short drive, the taps open and 24 hours to act.
4. Drain the tank again and flush the system with clean water. If you can still smell diesel, repeat the treatment.
5. Check the water filters. If your system has a filter, replace it, as it may have trapped hydrocarbon residue.

It’s also important to bear in mind that the problem may extend beyond the tank itself. If the taps have been opened since the spill, the contaminated water may have travelled through the pipes, so the whole circuit will need to be treated.

At this stage, it’s not a good idea to try to mask the smell or simply keep refilling the tank with water. What you need to do is remove the hydrocarbon residue with a product specifically formulated for the purpose.

Understanding why draining the tank may not be enough

Once you’ve found diesel in the water tank, draining it is a necessary step, but the job doesn’t end there.

Even if you appear to have removed all the contaminated liquid, residue may remain on the inner surfaces of the tank and in the pipework. That’s why a specific clean is needed before the system can be used normally again.

In addition, the distinctive smell of fuel can be a clear sign that residue is still present, but its disappearance should not be taken on its own as a guarantee that the system is completely clean.

The aim should be to treat both the tank and the pipes properly, following the specific instructions of the product used.

Using Ambiti Gasoil Stop to clean the system

Ambiti Gasoil Stop is a specialist degreaser developed to remove diesel and other hydrocarbons from vehicle water tanks and sanitation systems.

Its formula is designed to act on diesel and other hydrocarbons such as crude oil, benzene, toluene and ethylbenzene. It is currently sold in a 1-litre bottle.

This means you can tackle accidental contamination with a product designed specifically for this problem, rather than resorting to household detergents or other solutions that have not been formulated for motorhome water systems.

Applying Gasoil Stop correctly

To get good results, it’s important to follow the instructions for use provided by Ambiti.

Start by filling the tank with water to around three quarters of its capacity and adding 500 ml of Ambiti Gasoil Stop.

Next, drive the motorhome so that the product is distributed throughout the inside of the tank.

Then open the interior taps so that the mixture also flows through the pipes. This way, the treatment isn’t limited to the tank but also reaches the circuit through which the contaminated water may have passed.

Leave the product to act for 24 hours. After that time, drain the tank. Ambiti states that the procedure can be repeated if necessary.

Paying attention to the pipes as well

When you find diesel in the water tank, it’s easy to focus on the tank alone, but the pipes are part of the same system.

That’s precisely why the Gasoil Stop instructions include opening the interior taps during the treatment. This ensures the product flows through the pipework and doesn’t act only on the tank walls.

If the fuel has been in the system for some time or the taps have been used since the incident, paying attention to the whole circuit is even more important.

Avoiding home remedies to remove diesel

Faced with diesel in the water tank, you’ll come across all sorts of home remedies: washing-up liquid, vinegar, bicarbonate of soda or other cleaning products.

However, a motorhome’s water system includes tanks, pipes, seals and various components that require suitable products.

What’s more, we’re talking about removing hydrocarbons, so using a product specifically formulated for this purpose means you can follow a defined procedure and dosage.

Ambiti Gasoil Stop contains non-ionic and anionic surfactants and is specifically formulated as a degreaser for this application. When handling it, follow the precautions indicated by the manufacturer, including wearing gloves and eye protection and avoiding ingestion of the product.

Preventing future mistakes when refuelling

Once the problem has been solved, it’s worth adopting a few habits to stop it happening again.

Before refuelling or filling up with water, always clearly identify each filler inlet. If several people use the motorhome, they should all know where the fuel tank and the water tank are located.

It can also be helpful to add clear visual markers near the inlets when their position or design could cause confusion.

These small habits can save you a complicated clean-up and keep your water system working properly for many trips to come.

For everyday care, it’s also worth reading how to store water in your motorhome and maintain the tank, especially in hot weather.

Restoring the tank after accidental contamination

Finding diesel in the water tank of your motorhome or campervan is a problem that requires the right response, but there are specific solutions to deal with it.

Draining the tank, treating both its interior and the pipes, and carefully following the cleaning procedure are the key steps.

With Ambiti Gasoil Stop, the treatment is carried out with a product specifically developed to remove diesel and other hydrocarbons from this type of system.

Once the system is clean, refill the tank with drinking water and keep it in good condition on the road with Ambiti Potable Tabs water purification tablets.

And above all, once the incident has been resolved, clearly identifying the filler inlets will help prevent a simple oversight from becoming a problem again on your next trip.