Should I store my caravan water tanks empty or full?

In this blog post, we will answer the following question: Should I store my caravan water tanks empty or full? We will discuss the must-do-s before storing your caravan and how to maintain and clean the water tanks of a caravan.

Should I store my caravan water tanks empty or full?

You should store your caravan with empty water tanks. If you leave water in the tanks for a long period, your tank is likely to fill with viruses and bacteria that can affect health. To avoid this, you must know how to empty and clean the clean water tank of a caravan.

In fact, here are the must-do-s before storing a caravan long-term:

  1. Empty the water tanks: Drain and clean the two tanks (clean water and wastewater). 
  2. Keep the water pump warm: Take it apart and store it in a warm place. 
  1. Disinfect the toilets: It will be necessary to disinfect the tank (always with bleach), then to rinse it. 
  1. Clean the refrigerator: You can clean your refrigerator with vinegar or bleach and wipe it down with a clean cloth. 
  1. Empty and clean the cupboards: It is essential to completely empty and clean the cupboards. 
  1. Lift up the cushions and undo the beds: Air circulates with difficulty around mattresses and cushions.
  1. Release the blinds: We also recommend that you open the panoramic skylights slightly to prevent the joints from sticking together after a long period of disuse. 
  1. Wash the exterior of the caravan: Wash the body of your vehicle with a high-pressure jet. When it is dry, use a detergent and a soft brush to loosen the encrusted dirt, rinse quickly before the product dries.
  1. Protect the seals: The seals do not tolerate temperature variations and hate the cold. It is therefore necessary to remember to grease them after a long period of inactivity in order to avoid possible cracks. 

Winterizing is also the time to check the attachments of your outdoor accessories such as a top-box, an antenna, a ladder, a bike rack, etc. Allow your vehicle for a short 30 km ride (once a month is perfect!) To prevent the joints from drying out and oiling the engine parts.

You should clean the water tanks before storing your caravan

There are several ways to clean the clean water tank of a caravan. However, in this post, we focus on the two most reliable and accurate ways to accomplish this task.

Silver Chloride is a powerful bacterial and fungal killer. On the market, you can find it very easily in two presentations: powder or drops. In addition, this product packs a lot and a single bottle can be used multiple times.

So that you are clear about the measurements, 10,000 litres of water are purified for every 100 grams of silver chloride. You must add it when your tank is full and wait 2 hours for it to take effect.

Another option that is really useful when cleaning the tank is purifying tablets and their use is easier and more practical than that of silver chloride. You just have to add one pill for each litre of water and voila, completely drinkable water.

Once your drinking water tank is clean it can be disinfected. Note that disinfection does not “clean” the tank, it only kills the bacteria that after all cling to the pipes or the tank.

If the tank has water, the first thing is to empty it, use the tank drain valve, which has its intake in the deepest part of your tank.

The idea is to fill the freshwater tank with a 5% sodium hypochlorite solution, about 1 litre of solution for every 12 litres of fresh water. Chlorine should not be poured directly into the tank, prepare the solution outside and then fill your tank.

This mixture puts a 50 ppm (parts per million) concentration of chlorine in your water system, which will quickly kill harmful bacteria, viruses, and slime-forming organisms that may be living in your motorhome. A higher concentration of chlorine can damage the tank, pipes and other items, so you must be careful when measuring.

Open all the water outlets, one by one, allowing the chlorine solution to pass through all the circuits recorded in your installation.

Turn off the taps a couple of minutes after you can smell the chlorine in the water coming out of the tap.

Close everything and let your caravan rest for at least four hours, although if you leave it overnight, all the better. Reopen the taps and pump the remaining solution into your storage tanks.

Next, your entire drinking water system should be completely flushed with normal chlorinated tap water. Circulate the water through all the circuits for several minutes, until the smell of chlorine diminishes to the same level as that of city water.

Cleaning the grey and black water tank

The grey water tank is made up of the water that falls through the sink, shower or hand basin and the black water tank contains the water from the toilet. The caravan warns us when they are full and these deposits must be emptied only in authorized and authorized sites, which are usually located in campsites.

Emptying the grey water tank is also simple, you just have to place your vehicle near the authorized place and turn the stopcock that is located on the underside of the motorhome, the dirty water will start to come out until it is completely emptied.

In addition, you must also be careful with these deposits, as they can generate bad odours, so it would be appropriate to clean them regularly with specific products for their care.

Finally, the sewage tank, also known as the cassette, is located just below the toilet and must also be emptied in authorized areas. You just have to remove the tank, empty it into the sewer and clean it with the specific products. Afterwards, you must add a little water and put it back in its place.

Final advice

Freshwater tanks do not usually have slopes that facilitate their emptying, such as faecal or grey water tanks. The bottom is usually flat since the water is extracted by aspiration, through a tube that enters the tank from the top.

Remember that even if you have a simple method to empty the tank, introducing clearly dangerous water, no matter how good a filtration system you have, is a mistake. Above all, it is important to stay away from chemical contamination: pesticides, etc.

If you don’t use your caravan, keep the tanks (not just the drinking water one) empty and dry if possible. Not all tank drainage systems allow their complete emptying, many leave sediment at the bottom, which is still a design problem in my opinion, which should be solved as soon as possible!

Please let us know if you have any comments or questions about the content. 

FAQ on Should I store my caravan water tanks empty or full?

Where to dispose of the sewage?

The sewage is poured directly into an aseptic tank or cassette. The tanks or cassettes that collect the sewage have a rotating tube through which they are discharged into the corresponding drain, and which must be connected to an aseptic pit or the sewer

How does the water system of a caravan work?

In the caravan, it is only a small jet of water that lightly cleans the toilet. Very little water is used in each flush of the cistern. The tank is filled with a special liquid whose only function is to give a good smell. If you do not have this liquid, you can simply use water

How can we recycle greywater?

There are different technologies for recycling greywater: physical-chemical treatments (coagulation-flocculation, filtrations…), biological treatments or a combination of the two. Generally, these treatments are completed with filters and disinfection systems.

What are grey and black waters?

Gray water has a great difference since it does not contain faecal matter and its name is due to its condition of being in the middle point between wastewater and drinking water, in addition to having a cloudy appearance. Any water that contains human waste is considered black water.


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