The definitive guide to the caravan toilet cassette


The definitive guide to the caravan toilet cassette answers all your difficult after-dinner questions.

I remember the first time my wife, Kylie, insisted we get a caravan with a toilet cassette. My reaction was less than enthusiastic. Something along the lines of ‘you can’t be serious’. In all fairness to Kylie, my attitude has flipped 180 degrees and now I could not envisage a time where I might be tempted to buy another caravan without a dunny. It is just a wonderful modern convenience and a luxury when free camping for extended periods.

That said, the fact that using the caravan toilet involves physically removing a cassette full of excrement, wheeling it to the dump point and having to empty the contents into a shared cesspool is not exactly first-world living. Let’s face it, some dump points are pretty feral.

But there is so much more to this seemingly simple task that it fills the caravan and camping Facebook groups with many questions and an endless supply of opinions expressed in the answers. It’s hard enough to bring yourself to deal with your own sewage, let alone ask embarrassing questions about it. So here is our definitive guide to the caravan toilet cassette.


Push this button

showing the airflow button on a toilet cassette

You may have noticed the little button on the top of the cassette and wondered what it is used for. It is actually an air bleed valve that, when depressed, allows air to enter the cartridge as the contents flow freely out of the nozzle. The idea is that you carefully lower the nozzle to just above the drain hole, push the button and tip the contents out in a free-flowing action with minimal splashback. Make sure you don’t push this button too early or you’ll end up with excrement in all the wrong places.

Removable Wheels

The designers of the toilet cassette must certainly have put some thought into the process. The path from your caravan park site to the dump point is usually nothing more than a rough gravel path. It’s easy to understand how the wheels of the cassette can break in these conditions. Fortunately, the wheels simply pull away from the cassette and can be replaced with new ones.

Oil the seal

caravan toilet cassette seal

Many owners are not aware that the rubber seal at the top of the cartridge needs to be kept in good condition. They are prone to perishing, leading to leaks inside the caravan ensuite and no one wants that to happen. Fortunately, it’s a simple exercise. Just slide the cover back to expose the seal, spray it with a small amount of olive oil, ensuring the whole seal is covered and replace the cover. It’s that easy!

Don’t ignore the red light

On the top of your toilet inside the van, you may notice a red indicator light telling you the cartridge is full. Do not ignore this light, the results can be catastrophic if you do. Some of our more experienced readers may think this is bleedingly obvious but you would be amazed at how many times I’ve seen novice RVers cleaning out the inside of their vans because they didn’t realise what this light meant.


While we’re on the subject, there may be times when you return the newly emptied cassette to its cavity only to find the indicator light still on. This is normally traced back to the float inside the cassette getting stuck in the full position. If this happens, either remove the cassette and give it a tap on the side or give it another flush out with water. Both should resolve the problem.

My toilet won’t flush

The issue here may depend on which model toilet your RV has. If it is the sort with a separate flush water tank (Thetford C2), make sure this flush tank is full. If that doesn’t resolve the problem, the culprit will most likely be a jammed impeller pump. There are plenty of videos on YouTube explaining how to remove this pump and free the impeller but, if you don’t feel confident resolving this on your own, any caravan repairer will be able to sort this out very easily and cheaply. In extreme cases, the pump may need replacing.

If, after fixing the pump, it still won’t flush, the culprit is likely to be a blown fuse protecting the pump. Many RV toilets have a fuse located within the cassette cavity, either on the left side wall or down the back of the cavity. It’s a normal three-amp automotive fuse so it is easy to replace. Other things to check include all wiring connections within the cassette cavity as these are prone to corrosion and perishing.

Where should I empty my toilet cassette?

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First and foremost, you should always find a proper RV dump point. All caravan parks should have one but some don’t. If in doubt, ask the park manager. Most dump points are pretty obvious, being the familiar grey tub with a blue lid. Some definitely are not so obvious. We’ve seen everything from a porcelain toilet placed outside the amenities block to nothing more than a small and inconspicuous drain hole in the ground.

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Most towns across Australia have a public dump point and the majority are well signposted. If you’re having trouble locating one, there are a number of smart device apps that can tell you where the nearest dump point is. We use WikiCamps and have found it to be accurate and reasonably up to date. Be aware many of these apps rely on users to provide and update the information. They have been known to be wrong. If you’re in doubt, the local visitor information centre should be able to direct you to the correct location.

Whatever you do, NEVER empty your cassette into a stormwater drain or out onto the open ground. NEVER empty a cassette into a drop toilet. NEVER empty a cassette into a public toilet unless you are directed to do so by a park manager.

If you intend to do any long-term, remote free camping, consider carrying an additional cassette to extend your times between needing to visit a proper dump point.

What chemicals should I use?

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I’ve saved the hardest question until last.

Unfortunately, you will find it very difficult to get an answer that everyone agrees on. This is mainly because not all dump points are connected to a regular sewerage system. Many across regional and remote Australia are connected to septic tanks. Some may be even more primitive. You should only use proper RV toilet chemicals and only in concentrations according to the directions on the packaging. Always ensure they are marked ‘septic safe’.

You may have heard some people use products such as Nappy San and other similar chemicals. There is much debate about whether these products are septic safe and there is no way my opinion is going to sway readers either way. At the end of the day, it may well come down to the desires of those who are responsible for maintaining the individual dump point itself. Some managers may insist you do not empty your cartridge into their site if you use Nappy San. Some may not want any chemicals at all to go down their drain.

If you must use Nappy San, never use more than half a capful mixed with about one litre of hot water in your cassette.

We have started to use the Green2Go range of RV toilet concentrates. These are Australian made, septic tank safe, environmentally-friendly products that use beneficial bacteria to breakdown waste without the use of harmful chemicals. So far, they appear to work very well.

A final word:

Disposing of your daily excretions while travelling in your caravan or RV requires a completely different mindset to how you deal with it at home. It really isn’t as simple as pushing a button and flushing it away. You have to keep in mind that you are not the only person who could be affected by your actions. With a little thought, education and consideration, it certainly doesn’t have to be an erroneous chore for you or anyone else.

The definitive guide to the caravan toilet cassette: Tops Tips

Top tip 1

Avoid disposing of your toilet paper into your cassette. It bulks up, quickly filling your cassette and requiring more frequent emptying. Instead, place a small bin in your ensuite and line it with a nappy bag. Place your soiled toilet paper into the bag and dispose of it responsibly as you would with other garbage. You don’t have to purchase special toilet paper either.

Top tip 2

Most dump points have a tap nearby to allow you to rinse out your cassette after emptying it. The same can’t be said for many in remote areas. In order to ensure your cassette is as clean as possible, consider having a small container dedicated to holding rinse water for your cassette. Place a small amount of the toilet chemicals into the water to ensure the cassette is returned to the van as fresh as possible.

Top tip 3

At some point, you are going to have to use your toilet for number twos and, to be perfectly blunt, it will result in some unpleasant smells permeating through the rest of the van. If you’re intending to do a lot of free camping, especially for extended periods, consider fitting an SOG system to your RV toilet. These are extremely effective at keeping the odours to a minimum.

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Top tip 4

When emptying the cassette, be very careful where you place the cap. Many RVers have lost their caps down the drain of the dump point. Apart from the inconvenience to yourself, these can block the system, causing all sorts of havoc.

Top tip 5

If you need to measure out the amount of chemicals required for your cassette, use the measuring cup conveniently integrated into the cap.

Read next The dos and don’ts with the grey water controversy




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