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Camping and toilets, this topic can fill hours. When we meet other campers on the road, the conversation sooner or later always ends up at the quiet little toilet. This is not because we like to talk about toilets so much, but because this topic really affects everyone.

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

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. This 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 characterized by the fact that they do not require a connection to the sewer system. And this is how they work: Feces are collected in a container to which chemical substances are added. These are intended to prevent the formation of odors and at the same time serve as a disinfectant. They also help the waste and toilet paper to decompose more quickly. While porta-potties are usually emptied by specialized companies, a chemical cassette toilet may be emptied by yourself, but only at designated disposal stations.

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 possibility 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 liters is often common. Many fixed-tank toilets do not require chemical additives because they use SOG technology. This process prevents unpleasant odors.

Mobile chemical toilets:

These toilets consist of two parts placed on top of each other. On top are the seat, the toilet bowl, and the freshwater tank. At the bottom is the holding tank. Camping toilet Cassette toilets are permanently installed in the bathroom of the motorhome or campervan. The flush on the Porta Potti is usually a hand-operated pump system, so no electricity is needed for this. The two tanks are separated by a gate valve. A sanitation fluid in the waste tank breaks down the fecal matter.

Cassette toilet:

A cassette toilet is usually chemical and always permanently installed in the camper and campervan. It looks practically like a real toilet, but usually a little smaller. Through an outer flap, the feces can be removed. However, there are also cassette toilets that are filled with biodegradable liquids instead of the usual chemical substances. This makes the toilet contents more environmentally friendly, and it can be emptied into the sewage system without hesitation.

Dry toilet:

This toilet model is also often called a composting toilet. It works without water or chemicals. The feces simply fall into a bucket or bag directly under the toilet seat. After the passage, for example, bark mulch is dumped over it. This is because it binds the odor and can easily be turned into compost. A very environmentally friendly method. It is advisable to use particularly thin or easily decomposable toilet paper.

Composting toilet:

Compost toilets do not use water, and they separate solids from liquids. They are useful if you have a limited water supply and are part of a couple or single traveler. When used properly, they have no unpleasant odor. However, they can give off an odor similar to the smell of soil, but the exhaust fan takes the air out of the bowl to the outside. This is not ideal for families due to the fact that you have to change the tank often.

Advantages and disadvantages of a chemical toilet

One of the advantages of a chemical toilet is that it can be used on a mobile basis, whether at festivals, construction sites, in a garden shed, caravan, or motor home. It thus guarantees certain independence. Most cassette toilets also require quite a little space. However, there are also some disadvantages associated with a chemical toilet.

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

Relate: Water tank in the RV: What you need to know

RV Chemical Toilets


Which chemical to use for the toilet?

If you use a chemical toilet, you should also consider the additives. Some of them pose a real danger both to the environment and to your own health. Therefore, the principle should always be: The less the better. Chemicals used in some sanitary additives are these:

  • Glutaraldehyde. The characteristic of glutaraldehyde is its pungent odor. 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 to humans and can damage the genetic material (click here for 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.

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

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. Substances that biodegrade well and quickly are also not as effective for as long. Chemical manufacturers always try to achieve an optimum between storage life, duration of action, and degradation rate. Often not to the benefit of the environment.

Disinfectants are usually used as additives. These prevent the growth of odor-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. However, 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.

Relate: Water in RV: Guide for Beginners

Sanitary additives for caravans and motor homes

Keeping track of the wide 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 merely needs to be dropped into the tank, while liquid products require precise measuring. For all additives, however, you should follow the manufacturer’s dosage instructions.

Toilet paper for chemical toilets

Opinions are divided on toilet paper. Some swear by the special camping toilet paper that can be bought in stores. 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 commercial (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 trash can.

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. Both the flush water and waste tank additives are added from the outside of the tank and then topped up with a small amount of water. Do not add the sanitary additives directly through the toilet bowl. This can attack the slide valve seal of the tank.

Relate: How to Clean RV Fresh Water Tank

Chemical toilet broken – what to do?

If your holding tank is broken, 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.
At least, if you have a Thetford toilet installed because this manufacturer has 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. There, all components are listed with numbering. Once you know exactly what you need, you can order them from either your local camping retailer or Amazon.
  • Download the user manual and installation instructions: Under “Technical Support” you can find all the info for your model.
  • If there are videos with repair instructions, they are also listed under “Technical Support”. Especially for The titles of the tutorials are in English, but the videos themselves were shot without sound and are super understandable through the pictures alone. Especially for the 400 and 500 series, but also for the no longer available models from the 200 series, a large selection of step-by-step tutorials is 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.


Chemical toilets are still widely used in camping. In caravans or motor homes, they are usually installed as standard. Less common are toilets that do not require chemicals, for example, vacuum, separation, or dry toilets. For good reason, more and more campers are interested in this alternative. They not only grant more self-sufficiency but also represent a significantly lower burden on the environment. Those who nevertheless do not want to do without a chemical toilet should use the additives with great care, ensure good environmental compatibility and never simply dispose of the contents of its cassette in the environment.


✅ How do you use RV toilet chemicals?

Once you have a base of a couple of gallons of water in your black tank, simply press down on the flushing valve for your toilet and dump the liquid chemical down the toilet, or add the RV toilet tablets. Your RV toilet is now ready to use.

✅ Can you empty a chemical toilet into a normal toilet?

Apart from the obvious hygiene issues, the chemicals should not go straight into the sewerage system. … If you can’t find an official emptying point, your only option will be to flush the contents of your toilet down a normal WC, which may mean taking it back home.

✅ How often do you put chemicals in an RV toilet?

If it is just you and your spouse, once a week may be enough. A general rule of thumb is to wait until your tanks are about two-thirds full before emptying them. It creates a much better “flow” when dumping, making the process much more efficient.

Max Welder (rvneeded)

Max Welder (rvneeded)

Max Welder is a mechanic enthusiast. Currently, working at a small company. Experienced in electronics, car tools, and security systems. In his spare time, he writes articles for various blogs.

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