NL
Clean water tanks and well-rinsed pipes are the basis for safe drinking water during your holiday. Biofilm, deposits and odours quickly develop in standing water – especially after longer periods of non-use. With a thorough clean you prevent bacteria and annoying taste problems. It costs at most a few hours and keeps your water system fresh and reliable.
Why you should clean your water tanks at least twice a year
The fresh water tank in your motorhome may look clean when you empty it, but a thin layer of water often remains in corners, pipes and the boiler. When the vehicle is parked up or in warm weather, that begins to become contaminated. Biofilm – a slimy layer of bacteria – forms on the walls. Limescale builds up in the boiler and hot water taps.
Experts advise cleaning the entire water system at least twice a year. Plan this task just before the summer holiday and after a long winter lay‑up. If you use the motorhome intensively or leave it standing for long periods, cleaning more often is sensible. Maintenance rounds are a fixed part of a thorough motorhome check and maintenance. That way you can be sure of reliable drinking water while travelling.
How to clean the water system in seven steps
A thorough clean consists of emptying, treating, leaving to work and rinsing. This approach tackles the tank as well as all pipes, taps and the boiler. Follow these steps for the best result:
- Empty the fresh water tank completely and open all taps until no more water comes out. Don’t forget the hot water taps and the shower.
- Also drain the boiler via the drain tap. Water that remains standing becomes contaminated the quickest.
- Choose a suitable cleaning agent based on the level of contamination and the material of your system.
- Fill the tank with clean water and add the product according to the dosage on the packaging.
- Open all taps briefly so that the cleaning agent also reaches the pipes and the boiler. You can also take a short drive with the motorhome so the water circulates well through the system.
- Leave the mixture to act. Depending on the product this can take a few hours up to overnight.
- Drain the system completely and dispose of the dirty water at a suitable dump point. Then rinse several times with clean water until there is no smell, colour or foam left.
Which cleaning agents are suitable for motorhome water tanks
You can choose from various cleaning agents. Each has its own use and requires some care in handling. These are the main options:
Citric acid for limescale and light contamination
Citric acid is safe, effective and works well against limescale deposits. Many motorhome users choose this as their standard solution. Dissolve about 500 grams of citric acid in 50 litres of warm water. Warm water helps the powder dissolve better. Leave the mixture to work for a few hours and then rinse thoroughly. This method is suitable for the tank, pipes and boiler.
Cleaning vinegar for odour and light deposits
Vinegar helps with light contamination and reduces odour. Use about 0.5 litres of cleaning vinegar to 50 litres of water. Not every system reacts the same to vinegar, so if in doubt check whether the material of your pipes is resistant to acid. Always rinse very thoroughly, as residues give an unpleasant taste to the drinking water.
Chlorine bleach only for stubborn bacteria
Chlorine disinfects effectively, but only use it diluted and sparingly. Too high a dosage damages sensitive components such as rubber parts and seals. Always follow the manufacturer’s instructions and rinse extra thoroughly until all smell of chlorine has disappeared. This product is especially useful after a long period of non-use in warm weather.
Denture cleaning tablets for a quick clean
Many motorhome owners use denture cleaning tablets as a practical solution for a quick clean. The tablets dissolve easily and are mild enough for most systems. Again, always rinse thoroughly afterwards.
Special tank cleaner for peace of mind
Specially developed tank cleaners are tailored to motorhome water systems. They are user‑friendly and give peace of mind about material compatibility. Follow the dosage instructions on the packaging. This is the safest choice if you are not exactly sure what material your pipes are made of.
Don’t forget the boiler and waste water tank
Cleaning only the fresh water tank is not enough. The boiler is often warm for long periods, which means limescale and bacteria form more quickly. Always include the boiler in the cleaning process. Open the drain tap, let the boiler empty completely and then refill it with the cleaning mixture.
The waste water tank also needs regular maintenance. Soap, food scraps and dirt build up and cause bad smells. Rinse the waste water tank regularly with water and cleaner. You can use the same products as for the fresh water tank, but make sure you dispose of the dirty water at a suitable dump point.
‘ Standing water quickly starts to become contaminated, even in a clean tank. ’
Practical tips for fresh water on the road
Good cleaning at home is the foundation, but on the road the water system also needs attention. Refresh the water in the tank every three to four days. Standing water quickly becomes contaminated, even in a clean tank. Draw off water regularly and top up with fresh water.
Pay attention to all outlets. Clean not only the kitchen tap, but also the shower, hot water taps and any outdoor showers. Biofilm forms wherever water stands still. During cleaning, briefly run water through all outlets so that the product reaches everywhere.
Check filters and replace them annually. A dirty filter reduces water quality and can itself become a source of bacteria. Descale the boiler separately if you notice that the water heats up more slowly or if you see white deposits on the taps. This prevents damage to the heating element.
What to avoid when cleaning water tanks
Rinsing thoroughly is more important than the product itself. Residues of cleaner are the most common cause of bad taste or smell. Always rinse several times with clean water and run all taps until the water is clear and odourless.
Use chlorine and bleach only when really necessary. Overdosing attacks rubber, O‑rings and seals. Always check the instructions for the product and the specifications of your water system before you start.
Do not leave water standing unnecessarily. Empty the tank completely if the motorhome will be parked up for an extended period. A dry system prevents biofilm and bacterial growth better than standing water with a layer of cleaner.
Learn more about motorhome maintenance and preparation
Clean water tanks are just one part of proper motorhome maintenance. On the Traveler Tips website you’ll find much more reliable information about motorhome checks, preparation, routes and smart planning for your self‑organised holiday. Discover practical tips that help you travel comfortably and consciously.
Frequently asked questions
Clean the water tank and pipes at least twice a year, and always before departure after a period of non‑use. Plan a thorough clean if the motorhome has been standing still for longer or if you use the water system intensively. During the trip it is sensible to refresh the water in the tank every 3 to 4 days. When cleaning, do not just clean the tank, but also the pipes, taps and boiler, and rinse everything thoroughly.
Preferably use citric acid or a special tank cleaner that is suitable for water tanks and pipes, as these clean effectively and are generally material‑friendly. First empty the tank, pipes and boiler completely, fill with water and the chosen product, leave this to work for a few hours and let it circulate through all taps (including hot water). Then flush the whole system several times with clean drinking water until there is no smell, colour or foam left. Repeat this thorough cleaning at least twice a year and after longer periods of non‑use, and refresh your tank water every few days while travelling.
Common mistakes are using too high a dosage or the wrong product (for example too much chlorine), which can damage pipes and rubber parts or leave the water tasting of cleaner. Insufficient rinsing after cleaning often causes taste and odour problems while travelling. Cleaning only the tank and forgetting the pipes/boiler leaves contamination behind that can later come loose. Allowing water to stand too long without refreshing it (longer than a few days) also increases the risk of biofilm, odour and bacterial growth.
Empty the tank completely after every trip or period of use so that water cannot stand still for long and no biofilm forms. Clean the complete system (tank, pipes, taps, boiler) at least twice a year with, for example, citric acid or a special tank cleaner and then rinse several times. During longer trips, refresh the water every 3–4 days instead of just topping up old water. If possible, store the motorhome with the filler cap/vent and taps open so that any remaining moisture can evaporate.
