Toilet flushes – a subject that regularly raises questions, especially from touring newbies. For a start, can you travel with flush water in the tank? The simple answer is yes, you certainly can, and many people do.

That said, it’s not necessarily the best idea to drive with it completely full; partly because of the resulting weight, but also because it could potentially cause spillages. A litre or so of water should be fine and will be enough for emergencies.

Drain the flush fluid into a suitable receptacle and dispose of properly
Drain the flush fluid into a suitable receptacle and dispose of properly

In addition, in case there is a problem, I’d also suggest that you don’t put chemical additives into the flush water. Should any leaks happen to develop in the toilet flushing system, at least it will only be plain water spilling over your floor and carpeting!

So if you do use additives, add them when you top up the tank at your destination.

Several years ago, I took part in the Bailey Arctic Adventure expedition, touring thousands of miles on a trip where necessity dictated that we had to travel with water in the flush system. We had no problems then, and none since, either.

Replenishing flush tank on a Thetford toilet
Replenishing flush tank on a Thetford toilet

Many of the toilets fitted in UK motorhomes are manufacturers by Thetford. Its instructions state: “To prevent water damage to your vehicle, ensure that you don’t travel with a full flush water tank or with water in the toilet bowl.”

Filling a Dometic flush tank
Filling a Dometic flush tank

Dometic is another well-known brand, with products fitted in a wide range of motorhomes. Although the firm’s instructions don’t stipulate anything specific about travelling with water in the flush tank, they do state: “The slider must be closed while driving, and no liquid should be above the slider.” To clarify, the slider is the part that opens into the cassette holding tank at the base of the toilet.

Draining the system

Flush drain tube on a Thetford toilet
Flush drain tube on a Thetford toilet

It’s recommended to empty the flushing system when your motorhome won’t be in use for long periods of time, such as over the winter lay-up.

Otherwise, unpleasant outgrowths of algae – commonly known as ‘black bits’ – can form, and these might block the vehicle’s anti-syphon valves and the flush nozzle.

In Thetford products, there’s an external tube that unclips from the bung to be tilted down to drain. Bear in mind that if you use chemical additives, you will need to drain the fluid into a bucket and dispose of it properly.

For Dometic models, keep the button pressed to flush the toilet until the tank is completely empty, allowing water down into the cassette, and then empty that in the normal manner.

If you liked this… READ THESE:

Need to know… Going Unplugged

Need to know… Easy Electrics

Best motorhome cleaner for 2022

If you’ve enjoyed reading this article, why not get the latest news, reviews and features delivered direct to your door or inbox every month. Take advantage of our brilliant Practical Motorhome magazine SUBSCRIBERS’ OFFER and SIGN UP TO OUR NEWSLETTER for regular weekly updates on all things motorhome related.

Future Publishing Limited, the publisher of practicalmotorhome.com, provides the information in this article in good faith and makes no representation as to its completeness or accuracy. Individuals carrying out the instructions do so at their own risk and must exercise their independent judgement in determining the appropriateness of the advice to their circumstances. Individuals should take appropriate safety precautions and be aware of the risk of electrocution when dealing with electrical products. To the fullest extent permitted by law, neither Future nor its employees or agents shall have any liability in connection with the use of this information. You should check that any van warranty will not be affected before proceeding with DIY projects.