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Guide to camping toilets: Chemical toilet – how it works, sanitary additives, disposal

Camping and toilets is a topic that could fill hours. When we meet other campers on the road, the conversation sooner or later always ends up in the quiet little toilet. This is not because we like talking about toilets so much, but because this topic really does concern everyone.

Among campers, chemical toilets are probably the best-known version of mobile toilets. So today we’ll take a closer look at how they work, how they are cleaned and what advantages and disadvantages they bring with them.

How a chemical toilet works

Chemical toilets are not only used for camping, but also in other areas of life. Every one of us knows the famous porta-potty. It is often used at events or on construction sites. Chemical toilets are also used in buses or trains, sometimes in combination with a SOG system.

The porta-potty is one of the fixed chemical toilets. In the camping sector, the chemical toilet is also known as the “chemical cassette toilet”. All chemical toilets are characterised by the fact that they do not need a connection to the sewage system.

And this is how they work:

The faeces are collected in a container to which chemical substances are added. These are supposed to prevent odours from forming and at the same time serve as disinfectants. They are also supposed to help the faeces and the toilet paper decompose more quickly. This makes it easier to empty the tank later.

While porta-potties are usually emptied by specialised companies, a chemical cassette toilet may be emptied by yourself, but only at designated disposal stations.

What chemistry to use for the toilet?

Anyone who uses a chemical toilet should also be concerned with the additives. Some of them pose a real danger both to the environment and to one’s own health. Therefore, the principle should always apply: The less the better.

Chemicals used in some sanitary additives are these:

  • Glutaraldehyde
    Glutaraldehyde is characterised by its pungent odour. It is highly toxic to both humans and aquatic organisms. It is used for disinfection.
  • Formaldehyde
    Formaldehyde smells very pungent, has a germicidal effect and is used for disinfection.
    This substance is considered carcinogenic for humans and can damage genetic material (click here for the source).
  • Quaternary ammonium compounds
    This group of substances belongs to the surfactants and can also be very aggressive. They are used, among other things, in fabric softeners.

My advice:
Avoid additives that contain bacteria-killing substances such as formaldehyde and glutaraldehyde. Not only can they harm your own health, but they are also a nuisance to sewage treatment plants. Under no circumstances should such additives be dumped into nature, as they can be lethal to microorganisms.

The Blue Angel label provides guidance for the purchase of sanitary additives. It is associated with high criteria for the ingredients of the products. Click here to go to the website.

In this file you will find a market overview of chemicals from Ecocamping.

Biodegradable sanitary additives

Not everyone who uses a chemical toilet wants to use environmentally hazardous additives. That is why some resort to biodegradable agents. However, this designation can be misleading and does not imply that these substances are good for the environment.

I asked Wolfgang Pfrommer from the organisation Ecocamping about this:

CamperStyle: “Mr Pfrommer, what does biodegradable mean?”

Wolfgang Pfrommer: “It is defined according to the OECD guideline. According to this, all organic substances that are put into circulation must be biodegradable. 90 % of the substance must be completely degraded in a given time under standardised conditions. Substances that biodegrade well and quickly are also not as effective for as long. The chemical manufacturers always try to achieve an optimum between storability, duration of effect and degradation rate. Often not to the benefit of the environment.”

CamperStyle: “What substances are used in such agents and how harmful are they to the environment?”

Wolfgang Pfrommer: “Disinfectants are usually used as additives. These prevent the growth of odour-causing bacteria in the dirty water tank. The substances often have a direct bactericidal effect. Some substances change the conditions in the tank, for example by increasing the acid level (lowering the pH). Many bacteria do not like low pH values and do not grow or grow more slowly. A little citric acid or vinegar water can help. Some suppliers also add copper salts or silver ions as disinfectants. But these are not biodegradable and remain in the environment.”

CamperStyle: “What about the additives for the rinse water: are they really necessary or can they be replaced by other agents that are more environmentally friendly?

Wolfgang Pfrommer: “We recommend that campers avoid rinse water additives as much as possible and rather change the water more often.”

Sanitary additives for caravans and motorhomes

Keeping track of the large range of sanitary additives for the holding tank is not easy. They are available in liquid, powder or tab form. The main difference is in the handling. A tab just has to be thrown into the tank, while liquid products require precise measuring. For all additives, however, you should follow the manufacturer’s dosage instructions.

The additive WC-Mobil from AWIWA was recommended to us by Ecocamping as being particularly environmentally friendly.

Wolfgang Pfrommer: “Here, the bacteria are not killed but the dirt load is specifically treated with “good” bacteria. These additives contain strains of bacteria that aerobically (i.e. with oxygen from the air) break down the dirt load directly in the dirty water tank. These bacteria then displace the “stinky” anaerobic bacteria (unpleasant odours are caused by anaerobic decomposition = fermentation). This works very well. Many expedition campers now use these means, as in some cases in faraway countries it is often not possible to dispose of the dirty water in an orderly manner in a sewage treatment plant.”

Another good alternative we have found is the additive Ammovit, which converts the faeces into fertiliser within a very short time. This powder is very productive, but you should be careful when filling it into the tank: If it comes into contact with plastic or ceramics, it can leave ugly stains. We use this trick: Put a measuring spoon of Ammovit on a sheet of toilet paper, twist the whole thing together to form a small “packet” and then sink it into the open tank.

Toilet paper for chemical toilets

There is a difference of opinion when it comes to toilet paper. Some swear by the special camping toilet paper available in shops. Others have had good experiences with regular thin toilet paper.

It is important that the toilet paper decomposes as easily and quickly as possible so that it does not clog the tank. In our experience, this also works very well with a standard (maximum two-ply) paper from the supermarket.

Basically, it is advisable to have as little paper as possible in the tank so that emptying works without problems. An alternative is therefore to simply collect the paper separately in a waste bin.

Filling the toilet

When filling the camping toilet, be sure to follow the manufacturer’s instructions. “A lot helps a lot” does not apply to sanitary additives. The effect is not increased if you use more chemicals than necessary.

Both the additives for the flushing water and for the waste-holding tank are added from the outside into the corresponding container and then filled up with a little water. Do not add the sanitary additives directly through the toilet bowl. This can attack the tank’s slide valve seal.

Emptying the chemical toilet

To empty the toilet, the waste-holding tank is removed and the contents poured into the disposal station’s designated system.

Chemicals must never be dumped into the environment, but must be disposed of in appropriate places. A chemical toilet is no exception. Emptying them into nature is forbidden and can be severely punished.

Wolfgang Pfrommer from Ecocamping: “Under no circumstances should chemical additives be disposed of in toilets that are connected to a constructed wetland or a biological wastewater treatment plant at the campsite. Here, the chemical load is very harmful to the treatment performance.”

For emptying, these places come into question:

  • Campsites
  • Rest areas
  • Sewage treatment plants

Some campsites charge a fee for disposal, others offer it free of charge. The ADAC or Reisemobil International, for example, provide a very clear list of disposal options.

How often the toilet should be emptied depends on various factors. How often do you use it? How big is the tank? What additives do you use? How warm are the temperatures? The warmer it is, the more likely it is that the waste will start to smell. There is nothing wrong with emptying the toilet frequently if you have the opportunity to do so. Otherwise, emptying it after three days is a good idea.

If you use aggressive chemical additives, the faeces will be more neutralised than if you use environmentally friendly additives. This also influences the intervals between emptying.

If you empty the toilet daily, odours can hardly form. This usually only happens after a few days. If you add enough water, you can do without adding chemicals.

Cleaning a chemical toilet

After the toilet has been emptied, the next step should be to clean it. This is important so that the functioning is maintained. For example, the slide direction comes into contact with quite aggressive substances and can become leaky as a result.

To clean the chemical toilet, you should wear gloves and take care that your skin does not come into contact with the excreta or chemicals. There are usually water hoses at the disposal stations that can be used to flush out the toilet. You should not use any chemicals other than sanitary additives when cleaning, so that there is no undesirable reaction.

Some campsites now have special machines (e.g. from CamperClean) in which the cassette toilet is emptied and cleaned. To do this, you simply push the faeces tank into the machine and the technology takes care of the rest. The waste is sucked out, the tank is cleaned with water and then filled with the appropriate amount of water and a microbiological sanitary additive.

Advantages and disadvantages of a chemical toilet

One of the advantages of a chemical toilet is that it can be used on the move, whether at festivals, construction sites, in a garden shed, caravan or motor home. It therefore guarantees a certain degree of independence. Most cassette toilets also require very little space.

However, there are also some disadvantages associated with a chemical toilet.

  • It may only be disposed of in appropriate places and must be emptied approx. every three days. This limits self-sufficiency.
  • Many additives are a great burden on the environment and can damage health.
  • It needs water for operation. This is a valuable commodity when camping.
  • It needs to be cleaned thoroughly. This involves a time and/or financial outlay if, for example, a vending machine is used.
  • The additives and special camping toilet paper are relatively expensive.

The different types of chemical toilets

In addition to the porta-potty and the cassette toilet, there is also a portable solution. Those who do not have the space to install a cassette toilet in their camper can fall back on these portable variants.

For larger vehicles, there is the option of using a fixed tank. In this case, the toilet is directly connected to a large tank. The capacity depends on how much space is available, but 100 litres is often common. Many fixed-tank toilets do not need chemical additives because they use SOG technology. This process prevents unpleasant odours.

Well-known manufacturers of chemical cassette and portable toilets :

  • Thetford
  • Dometic
  • Enders
  • Berger camping toilet
  • Fiamma

Chemical toilet broken – what to do?

If your holding tank is defective, you don’t necessarily have to buy a new one for a lot of money. You can repair some things yourself with latex gloves, a screwdriver, a little patience and the right spare part.

Thetford C-400 Fresh Up Set
128.90 EUR
State: 29.09.2022 10:18 time
Buy now on Amazon
SOG 2 Typ D WC-Entlüftung für C400
235.10 EUR
State: 29.09.2022 10:18 time
Buy now on Amazon

At least if you have installed a Thetford toilet, because this manufacturer provides very detailed documents and tutorials for many models, with which the most common problems can be solved on your own:

  • Finding a spare part: First select the appropriate toilet model on the website. Then click on “Spare parts” in the menu bar at the top and download the pdf file. All parts are listed there with numbering. If you know exactly what you need, you can order the products either from your local camping dealer or from Amazon.
  • Download the operating instructions and installation guide: You can find all the information about your model under “Technical support”.
  • If there are videos with repair instructions, they are also listed under “Technical Support”. The titles of the tutorials are in English, but the videos themselves were shot without sound and are super comprehensible through the pictures alone. Especially for the 400 and 500 series, but also for the models from the 200 series that are no longer available, there is a large selection of step-by-step instructions available, for example on repairing and replacing the slider, the seals, the swivel arm, the aeration knob and the float.
  • Tip: If you don’t know which toilet or tank model you have, you can find out from your caravan or motorhome dealer using the chassis number.

Unfortunately, Dometic and Enders “only” have operating and installation instructions on their websites. If the worst comes to the worst, you should contact customer support directly. Fiamma also provides spare parts overviews for the individual models.


Chemical toilets are still frequently used in camping. They are usually fitted as standard in caravans or motor homes. Less common are toilets that do not require chemicals, for example vacuum toilets, partition toilets or dry toilets. For good reason, more and more campers are interested in this alternative. Not only do they provide more self-sufficiency, but they also have a much lower impact on the environment.

Those who nevertheless do not want to do without a chemical toilet should use the additives with great care, make sure they are environmentally friendly and never simply dispose of the contents of their cassette in the environment.

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