The green and sustainable alternative to the cassette toilet - Composting toilet for motorhomes and camping

The thing about "having to"

Everyone has to "have to" sometimes.

Whether at home, at work or while travelling. On average, a healthy adult excretes one and a half to two litres of urine plus solids every day, for which, statistically speaking, he or she visits the toilet up to seven times.

At home in the comfort of your own home or at work in the office, you don't worry about such trivialities.

Toilet lid up, small or large business done, cleaned with toilet paper, then flushed properly and done! Everything is easy.

It's a different story when travelling. Especially when you're travelling in a camper van or caravan.

The fresh water for flushing doesn't come from the supply line and the liquid and solid waste doesn't automatically end up in the sewage system.

So how does it work with the "must" when travelling on the move?

In the beginning was the outhouse

When camping was in its infancy, people shouldered their shovels and set off into the bushes.

At campsites, people used to go to the outhouse with their own toilet roll under their arm. Although the toilets were strictly separated into male and female, they stank to high heaven in summer.

The arrival of modern sanitary facilities on campsites brought relief.

The only difference was that the "quiet little toilet" was not as quiet and private as at home. After all, you shared it with other campers. And those who had to go out at night in wind and weather sometimes cursed the camping holiday.

So the desire for a toilet of one's own in the rolling holiday domicile soon arose.

In the early 1960s, Frank Sargent, an imaginative American, invented a portable toilet with a bowl, lid and flush water tank. Underneath, separated by a sliding device, was the black water tank.

The first cassette toilet came onto the market in 1988, and today it is installed in almost all motorhomes. A classic success story with a happy ending! Or is it not?

When horror lurks in the cassette tank

Anyone who has only once dragged the bulging cassette tank of their camping toilet to the emptying station and poured it down the sink knows immediately that they would never want to do this again.

The mixture of liquid, solids and toilet paper stinks like the plague and looks highly unappetising.

Even seasoned men sometimes have problems getting through the disposal procedure with dignity, despite wearing protective gloves and a nose clip.

Chemical sanitary additives, which are placed in the cassette, are supposed to provide relief from the disgust factor and gag reflex.

These chemical products are designed to decompose toilet paper and faeces. So that everything slips effortlessly when you pour it out. So much for the theory.

In practice, a watery gush often alternates with lumpy solids. If you want to avoid the resulting splashes, you have to have or make long arms.

Especially since a filled toilet cassette can weigh almost 20 kilograms!

Sewage treatment plants and nature do not like chemical additives

The yellow-brown colour of the collected waste is improved by the addition of dyes.

Green, blue or purple is what comes out of the cassette tank, which is supposed to give the impression of "pure nature".

In reality, the chemical additives are anything but environmentally friendly. Therefore, if chemical sanitary additives are used, the cassette tanks may only be emptied at special disposal stations.

The foul smell that almost makes you fall out of your flip-flops when emptying the cassette tanks is masked by added fragrances.

However, they are so penetrating that after a short time they are not limited to the motorhome bathroom but waft around the entire vehicle.

It gets really bad when these chemical additives end up in nature through carelessness or wantonness. This can destroy entire ecosystems.

Yet it is precisely us campers who are so drawn to untouched, intact nature. No camping without nature. It is a sacrilege if we damage it with what we leave behind!

The Cassette Emptying Tyranny

Apart from the unappetising emptying, there is another problem with the classic cassette toilet:

It is always full when you need it least.

For example, when you're standing by a crystal-clear lake in Sweden, a wild and romantic fjord in Norway, in a pristine valley in the Dolomites. Or when you can spend the night with an olive farmer in the middle of an olive grove or in a Scottish village right next to a whisky distillery.

The heart says, "I want to stay!"

The cassette grumbles, "I'm full, take me to the nearest disposal station!"

I wonder who gets the short end of the stick?

Some campers extend the disposal intervals by carrying a spare cassette tank.

When the first cassette is full, the second one is quickly placed in the cassette slot. This procedure buys time. But it is not a solution to the tiresome disposal problem.

The great camping freedom ends the moment you are forced by your own toilet to set off for the next disposal station.

How do you solve the toilet dilemma when travelling on the move?

By rethinking. By reorienting oneself. When it comes to toilets, they take a different and even greener and more sustainable approach.

In principle, the solution is simple and ingenious. With the composting toilet for motorhomes and camping, you kill several birds with one stone.

Because a composting toilet...

  • Does not require chemical additives
  • Does not require water for rinsing
  • Can be disposed of (almost) everywhere
  • Works odourless
  • Is uncomplicated to use and clean
  • Fliegen oder anderes Krabbelgetier sind bei der Trenntoilette natürlich ebenfalls kein Thema

How does a composting toilet work?

Quite simple. A dry composting toilet lives up to its name by separating - the liquid from the solid excreta.

Unlike normal toilets, the composting toilet has a collection container for urine and one for solids. To make this composting effortless when going to the toilet, there is a urine separator in the toilet bowl.

It is shaped in such a way that it takes into account the anatomical features of the human body: There is a large opening at the back (with or without a flap, depending on the model) through which the faeces fall into the solids container.

At the front, the urine flows through a funnel-shaped hole into the urine container.

This is usually a portable plastic canister. However, it is also possible to install a fixed urine tank.

--> More on the topic: How a composting toilet works, can be found here (please click).

Solids tank in the composting toilet - scattering instead of flushing

The solids container is basically nothing more than a large bucket cut to the size of the composting toilet.

A bag (preferably made of compostable material) is attached to it to collect the solids.

The toilet paper can also be placed inside. After using the toilet, you do not flush with water, but put a handful of absorbent grit into the solids container.

compostingThis is why the composting toilet is sometimes also called a dry composting toilet or dry toilet.

The grit binds the residual liquid and prevents unpleasant odours from developing.

Suitable litter materials include coconut fibres, sawdust, fine bark mulch and small animal or cat litter.

If a small fan is connected on a 12-volt basis to provide ventilation, the use of litter can sometimes be dispensed with.

--> Info about composting toilet/dry toilet types for motorhome and camping (please click)

Disposal: Close the bag and throw it in the bin!

When the solid waste container is two-thirds full, tie the bag at the top and dispose of it in the residual waste bin.

The same is done with baby nappies! This means that you no longer have to go to a disposal station to empty the solid waste container!

A public waste bin, which can be found almost everywhere on the road, is completely sufficient! What a relief!

Depending on the size of the solid waste container and the number of people travelling with you, emptying is due every two to three weeks.

Or put the bag on the compost

A dry composting toilet for motorhomes and camping is wonderful for garden owners who have the option of composting.

Provided you use 100 per cent biodegradable and compostable bags, the filled bags can be put on the compost where they will rot in just under two years.

A thermal composter, in which higher temperatures are generated during decomposition, shortens the composting process and ensures that any pathogenic bacteria or germs present are killed.

In this way, the composting toilet becomes a composting toilet at the same time, from which valuable fertiliser is obtained for the plants in the garden. A perfect cycle!

In the green or brown "organic waste bin", on the other hand, bags from the composting toilet have no place, as they take longer to decompose than normal garden waste and thus cause problems for the disposal companies.

Solid fuel tank with crank and ventilation for greater self-sufficiency

Some dry composting toilets for camping and motorhomes work without bags and therefore score with even longer emptying intervals.

In these types of composting toilets, an externally operated crank in the solids container, combined with a fan, mixes and aerates the mixture of solids and grit.

The constant aeration removes residual moisture from the solids, which both prevents odour formation and reduces the volume of waste.

When the solids container is about two-thirds full or the crank is difficult to move, remove the container and dispose of the whole thing either in the dustbin or on the compost heap.

Without having to use a nose clamp or protective gloves. And completely without the use of chemicals.

--> Blog: What you should bear in mind when installing a composting toilet in your motorhome (please click)

What happens to the urine from the dry composting toilet?

Here, too, no one has to turn up their nose.

The urine is collected at the front in the urine canister, which is secured against slipping or tipping over while driving.

When the urine container is almost full, you screw the lid onto the canister and dispose of the urine either in a normal toilet or in the sewage system.

Without it splashing on shoes or trousers or solids blocking the canister's spout. Since urine is usually bacteriologically sterile, garden owners can use it diluted with water for fertilising.

The prerequisite for this, however, is that one does not take any medication.

Separate so that nothing smells and stinks

"But urine stinks!"

This is an objection that many who use a composting toilet regularly get verbally slapped around the ears.

"Not true!", users of urine-diverting toilets can reply with a clear conscience.

Urine only stinks when it is mixed with solids and water and evaporates through the onset of putrefaction processes, including ammonia.

This is exactly what happens with the classic cassette toilet. When emptied, it stinks to high heaven!

If the urine is collected separately, as in the composting toilet for motorhomes and camping, nothing stinks. It is therefore not necessary to cover it up with chemical additives.

A composting toilet is completely odourless, provided it is operated correctly.

Composting toilet - A gain of precious holiday time 

Since urine makes up 90 percent of human excreta, the urine container of the composting toilet must be emptied more often than the solid waste container.

Nevertheless, one is spared the often tedious and time-consuming search for disposal stations because the urine can be poured into a public toilet or into the sewage system without any problems, for example.

This way you don't lose valuable holiday time! A composting toilet in the motorhome or caravan means more "quality time".

Reduce your own water footprint with the dry separation toilet

Water, or pure drinking water, is a valuable and increasingly scarce commodity. And thus much too good to literally go down the drain when flushing the toilet.

With a cassette toilet, two people use an average of five to six litres of water per day for flushing. If you have a water tank in your motorhome that holds 100 litres of fresh water, a twentieth of the on-board water supply is wasted every day just for the toilet.

Wouldn't it make more sense to save the water and thus stay longer at your favourite place in the middle of the forest or by the sea?

With a composting toilet in the motorhome, this is exactly what is possible. A composting toilet does not need a single drop of water due to the proven and safe separation system.

This not only saves resources, but also money. Because at most supply and disposal stations, you have to leave a few euros for refuelling with fresh water.

As far as environmental friendliness is concerned, the composting toilet for motorhomes scores points twice over:

On the one hand, no drinking water is wasted for flushing, and on the other, no black water contaminated with urine and solids has to be recycled in the sewage treatment plant. In this way, the composting toilet makes a significant contribution to reducing your own water footprint.

Care without problems

The composting toilet also needs some care.

To ensure that the use of the composting toilet remains hygienic and pleasant, the urine separator or the toilet bowl should be sprayed with a little vinegar water and wiped out with toilet paper every day or as needed.

The toilet paper can then be disposed of in the solid waste container.

The urine canister should be briefly rinsed with a solution of vinegar and water or citric acid dissolved in water after each emptying.

This prevents the formation of urine scale, which can not only be very stubborn but also smells unpleasant.

If the solid waste container is used without a bag, it should also be rinsed out after emptying.

All in all, however, cleaning a composting toilet is quicker and less problematic than cleaning a cassette toilet, which has many corners and edges that are difficult to reach.


  • By not using chemicals and water, a composting toilet is one hundred percent sustainable and environmentally friendly
  • Since you are no longer dependent on disposal stations and the disposal intervals are significantly longer, you gain self-sufficiency and freedom when travelling on the move
  • Thanks to the tried-and-tested composting system, there are no odours, neither during use nor when emptying
  • Emptying and disposal are child's play
  • Composting toilets save weight and thus increase the possible load
  • The use of special, fast-dissolving (and expensive) toilet paper is not necessary
  • Children can also use the composting toilet by using a special child seat
  • Because there is no need for expensive chemical additives and water for flushing, a composting toilet reduces the burden on travel budgets
  • All good reasons to choose an alternative to the cassette toilet

And when will you switch to a composting toilet?

TEXT: Heike Kügler-Anger

Take a look at the overview of the 6 best composting toilets for mobile homes, summer houses or TinyHouses.